mmm 


COMPRISES    STANDARD    WORKS 
In  eT«ry  department  of  instruction  and  of  every  grade.    The  teacher  in  want  of  a  took  for  any  par- 
eor  class  will  always  find  the  best  of  its  kind  in  our  catalogue.    No  otter  series  evem 
lla^s  toTas  compSe  as  this.    None  is  so  extensive  or  so  judiciously  scle^d.    Among  so  many 
Zera  Wgh  standard  of  merit  is  maintained,  as  it  is  our  aim  never  to  permit  our  in^riflt  upon  * 

poor  or  unworthy  book.    It  isjihso  ™*^*J^*t^L£?£L  JJS2  2£toKrUBMt 

countr *    ~" Ll       "~  *-—  ^  _         ^    ^ 


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GIFT  OF 
Harry  East  Miller 


e,  and  from  theil 
olumes  are 
e  in  itself.  T?J* 
'or  every  want  di 
%ers,  in  smaller 
to  the  companion 

Surveying, 

illions  have  been 

published  to  tak« 

m, 

,  others  to  follow. 

isually  forgotten, 

>f  groupuig  about 

,  Physical.— 

ither  series.    From 
)  book  he  wants. 
Philosophy, 

end  all  precedent; 

bject  lessons  and 

nan,  Freneht 

ithors,  with  signal 

o's  Orations, 

d  elegant  editions. 

rd  texts  published 

nnotated  Authors, 
of  language— De- 
Lexicon— NORTH. 

versal— BERARD'S 
esiastical  Hist, 
ational  Steel  Peaa 
rds— ALLEN'S  MJ/J> 

osophy— PORTER'S 
WOOD'S  Botany— 

hology— HTTNTINO- 
Manual— AxDKN'a 

terattrre,  as  PAOllV 

.ssistant,  &c. 


A  DESCBIPTIVE  CATALOGUE  of  all  these  and  many  more  may  be  obtained  by  enclosing  a 
stamp  to  the  Publishers, 

A.  S.  BABHES  &  COMPAHY, 

National  Educational  Publishers, 
111  &  113  WILLIAM  STREET,  NEW 


THE  WOEMAN  SERIES  IN  MODERN  LANGUAGE. 

A  COMPLETE  COURSE  IN  GERMAN, 

By  JAMES  H.  WORMAN,  A.M. 


ELEMIEISTTARY 

GERMAN 
COLLEGS-IATE  GERMAN  READER, 

G-ERMAN  READER, 
G-ERMAN  COPY-BOOK^,  GERMAN  ECHO. 

HISTORY"   CT&    GERMAN    LITERATURE, 

GERMAN    ANID    ENGLISH    LEXICON", 

I.  THE  GERMAN  GRAMMARS  of  Worman  are  widely  preferred  on  ac- 
count of  their  clear,  explicit  method  (on  the  conversation  plan),  introducing  a  system 
Of  analogy  and  comparison  with  the  learners'  own  language  and  others  commonly 
studied. 

The  arts  of  speaking,  of  understanding  the  spoken  language,  and  of  correct  pronun- 
ciation, are  treated  with  great  success. 

The  new  classifications  of  nouns  and  of  irregular  verbs  are  of  great  value  to  the 
pupil.  The  use  of  heavy  type  to  indicate  etymological  changes,  is  new.  The  Vocabu- 
lary is  gynonymical—&l»o  &  new  feature. 

II.  WORMAN'S    GERMAN  READER    contains   progressive    selections 
from  a  wide  range  of  the  very  beet  German  authors,  including  three  complete  plays, 
which  are  usually  purchased  in  separate  form  for  advanced  students  who  have  com- 
pleted the  ordinary  Reader. 

It  has  Biographies  of  eminent  authors,  Notes  after  the  text,  References  to  all  Ger- 
man Grammars  in  common  use,  and  an  adequate  Vocabulary;  also,  Exercises  for 
translation  into  the  German. 

III.  WORMAN'S   GERMAN  ECHO  (Deutsches  Echo)    Is    entirely  a  new 
thing  in  this  country.    It  presents  familiar  colloquial  exercises  without  translation, 
and  will  teach  fluent  conversation  in  a  few  months  of  diligent  study. 

No  other  method  will  ever  make  the  student  at  home  in  a  foreign  language.  By  this 
he  thinks  in,  as  well  as  speaks  it.  For  the  time  being  he  is  a  German  through  and 
through.  The  laborious  process  of  translating  his  thoughts  no  longer  impedes  free 
unembarrassed  utterance. 


¥  (MAN'S  COMPLETE  FRENCH  COURSE 

IS  INAUGURATED  BY 

H-'EOHO     IDE     IP.A.IRIS, 

Or,  "French  Echo;"  on  a  plan  identical  with  the  German  Echo  described  above. 
This  will  be  followed  in  due  course  by  the  other  volumes  of 

THE   FRENCH   SERIES, 

viz.: 

A   COMPLETE  GRAMMAR,  \A    FRENCH    READER, 

AN  ELEMENTARY  GRAMMAR,  \  A    FRENCH    LEXICON, 
A  HISTORY  OF  FRENCH  LITERATURE. 


WORMAN'S   WORKS 

are  adopted  as  fast  as  published  by  many  of  the  best  institutions  of  the  country.    In 
completeness,  adaptation,  and  homogeneity  for  consistent  courses  of  instruction,  they 

are  simply 


TJNUI  v  A:L:ET>  . 


±3      ct, 


CO      Jb 

evi    - 


I 


o     S 

II 

>-,     co 


03 


U  .J 

,\  Ll/'J^  -J  1 


REVISED   EDITION,  WITH   NEW  NOMENCLATURE. 


FOURTEEN   WEEKS 


IN 


CHEMISTRY 


BY 
J.  DORMAN    STEELE,  PH.D., 

AUTHOR  OF  THE   FOURTEEN-WEEKS  SERIES   IN   PHYSIOLOGY,   PHILOSOPHY, 
ASTRONOMY,  AND   GEOLOGY. 


bright  and  glorious  is  that  revelation 
Written  all  over  this  great  world  of  ours. " 

LONGFELLOW. 


A.    S,    BARNES    &    COMPANY, 

NEW  YORK,  CHICAGO  AND  NEW  ORLEANS. 
1876. 


TIJE  FOURTEEN  WEEKS'  COURSES 

IN 

NATURAL    SCIENCE, 

BY 

J.  DORMAN    STEELE,  A.M.,  PH.D. 

Fourteeij  Weeks  iq  Natural  Philosophy,  .  .  $i.50 
Fourteeij  Weeks  iq  Cl^ernjstry,  (2  Editions)  1.50 
Fourteeq  Weeks  iij  Descriptive  ^stroijomy,  .  1.50 
Fourteeij  Weeks  iq  Popular  Geology,  .  .  1.50 
Fourteeij  Weeks  iq  Hunjan  Physiology,  .  .  1.50 
A  Key,  containing  Answers  to  the  Questions 
and  Problems  in  Steele's  14  Weeks' Courses,  1.50 

4   HISTORICAL  SERIES, 

on  the  plan  of  Steele's  14  Weeks  in  the  Sciences, 

A  Brief  History  of  tfye  United  States,    .     .    1.50 
A  Brief  tyistory  of  France, 1.50 

The  publishers  of  this  volume  will  send  either  of  the  above  by 
mail,  post-paid,  on  receipt  of  the  price. 

The  same  publishers  also  offer  the  following  standard  scientific 
works,  being  more  extended  or  difficult  treatises  than  those  of 
Prof.  Steele,  thduglj  sttil  of  A]fadj»hJic:graJeJ.  * 

Peck's  Gaijot's'jNutural  tyfilpsupKyi..:     .     .  1.75 

Porter's  .Prijcifjles  of1  jClja^istry,      6    r.v  .  2.00 

Jarvis'/Ayiifll&gy,  ai$  ta^fis  ;of  If e^lfv,.^  .  1.65 

Wood's  Botanist  aijd  Fforist*   .    .    .    /    .  2.50 

Cljanjbers'  Elements  of  Zoology,   ....  1.50 

fljclntyre's  Astronomy  and  the  Globes,    .     .  1.50 

Page's  Elenjeijts  of  Geology, 1.25 

Address  A.  S.  BARNES  &  CO., 

Educational  Publishers, 

NEW  YORK  OR  CHICAGO. 

ENTERED  according  to  Act  of  Congress,  in  the  year  1873,  by 

A.    S.    BARNES    &    CO., 
In  the  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the 

Southern  District  of  New  York. 
STEELE'S  CHEM. 

GIFT  Off 


PREFACE 

TO     THE     FIRST     EDITION 


IN  the  preparation  of  this  little  volume  the  author  lays 
no  claim  to  originality :  his  has  been  the  far  humbler 
task  of  endeavoring  to  express,  in  simple,  interesting 
language,  a  few  of  the  principles  and  practical  applica- 
tions of  Chemistry.  There  is  a  large  class  of  pupils  in 
our  schools  who  can  pursue  this  branch  only  a  single 
term,  the  time  assigned  to  it  in  most  institutions.  They 
do  not  intend  to  become  chemists,  nor  even  professional 
students.  If  they  wander  through  a  large  text-book,  they 
become  confused  by  the  multiplicity  of  strange  terms, 
which  they  cannot  tarry  to  master,  and,  as  the  result,  too 
often  only  "  see  men  as  trees  walking."  Attempts  have 
been  made  to  reach  this  class  by  omitting  or  disguising 
the  nomenclature  ;  but  this  robs  the  science  of  its  mathe- 
matical beauty  and  discipline,  while  it  does  not  fit  the 
student  to  read  other  chemical  works  or  to  understand 
their  formulae.  The  author  has  tried  to  meet  this  want 
by  omitting  that  which  is  perfectly  obvious  to  the  eye — 
that  which  everybody  knows  already — that  which  could 

M81832 


Viii       PREFACE    TO     THE    FIRST   EDITION. 

not  be  long  retained  in  the  memory — and  that  which  is 
essential  only  to  the  chemist.  He  has  not  attempted  to 
write  a  reference-book,  lest  the  untrained  mind  of  the 
learner  should  become  clogged  and  wearied  with  a  multi- 
tude of  detail.  He  has  sought  to  make  a  pleasant  study 
which  the  pupil  can  master  in  a  single  term,  so  that  all 
its  truths  may  become  to  him  "  household  words."  Bot- 
any, Natural  Philosophy,  and  Physiology  are  omitted, 
since  they  are  now  pursued  as  separate  branches.  Un- 
usual importance  is  given  to  that  practical  part  of  chemi- 
cal knowledge  which  concerns  our  every-day  life,  in  the 
hope  of  bringing  the  school-room,  the  kitchen,  the  farm, 
and  the  shop  in  closer  relationship.  This  work  is  de- 
signed for  the  instruction  of  youth,  and  for  their  sake 
clearness  and  simplicity  have  been  preferred  to  recondite 
accuracy.  If  to  some  young  man  or  woman  it  becomes 
the  opening  door  to  the  grander  temple  of  Nature  be- 
yond, the  author  will  be  abundantly  repaid  for  all  his 
toil. 

NOTICE.  —  The  publication  of  "Fourteen  Weeks  in 
Chemistry,"  with  the  Old  Nomenclature,  is  STILL  CON- 
TitfUED.  Copies  may  be  obtained  of  all  booksellers,  or 
of  the  publishers,  A.  S.  BARKES  &  Co.,  New  York  and 
Chicago. 


PREFACE 

TO    THE     REVISED     EDITION 


SIX  years  ago,  at  the  solicitation  of  his  fellow- 
teachers,  the  author  offered  this  work  to  the  pro- 
fession. Having  been  prepared  for  the  use  of  his  own 
classes,  and  embodying  his  oral  instructions,  it  naturally 
partook  of  the  peculiarities  of  that  method.  The  desire 
was  to  interest .  pupils  in  scientific  study.  He  be- 
lieved that  a  chemical  fact  is  no  less  a  truth  because 
made  attractive  by  an  imaginative  garb.  If  thus  a  child 
could  be  won  to  its  consideration,  the  intrinsic  beauty  of 
the  subject  would  lure  him  on,  and  so  at  last  he  would 
come  to  pursue  it  into  the  labyrinths  of  dry,  technical 
works. 

The  hearty  reception  of  the  book  at  once  and  its  con- 
stantly increasing  sale,  the  demand  for  an  entire  series 
on  the  same  plan,  words  of  approval  from  educators 
whose  commendation  it  was  a  great  satisfaction  to  have 
won,  the  fact  that  several  other  series  based  upon  the 
same  general  idea  have  since  appeared,  and,  above  all, 
the  assurance  that  the  books  have  gone  into  hundreds 


X       PREFACE    TO     THE    REVISED    EDITION. 

of  schools  where  science  had  never  been  taught  before — 
have  convinced  the  author  of  the  inherent  correctness 
of  his  view. 

A  demand  having  arisen  for  the  admission  of  the  new 
nomenclature  into  the  book,  the  opportunity  is  gladly 
taken  of  making  such  revision  as  the  daily  use  of  the 
work  in  the  class-room,  and  the  advice  of  others,  have 
suggested. 

The  author  would  here  acknowledge  his  special  in- 
debtedness to  the  many  teachers  who,  sympathizing  with 
his  plan  of  popularizing  science,  have  pointed  out  what 
they  considered  defects  in  its  execution,  and  given  him 
the  benefit  of  such  illustrations  and  methods  as  they  have 
found  serviceable.  The  value  of  these  criticisms  has 
been  shown  in  the  increased  worth  of  each  edition  of  this 
series. 

The  usual  authorities  have  been  freely  consulted  in 
this  revision.  The  following  have  been  found  of  es- 
pecial service :  Miller's  Elements  of  Chemistry  (4th 
London  Edition),  Tomlinson's  Miller's  Inorganic  Chem- 
istry, Koscoe's  Lessons  in  Chemistry  (London,  1869), 
Bloxam's  Metals,  and  Fownes's  Manual  of  Chemistry 
(London,  1873).  In  addition,  reference  has  been  had  to 
the  works  of  Cooke,  Draper,  Nichols,  Fresenius,  Mus- 
pratt,  Faraday,  Watts,  Stockhart,  Moffit,  Gmelin,  Griffin, 
Tyndall,  Odling,  Noad,  "Williamson,  Wilson,  Galloway, 
Youmans,  Regnault,  Thomson,  Valetin,  Gregory,  Porter, 
Will,  and  many  others. 


SUGGESTIONS    TO    TEACHERS. 


IT  is  advised  that  in  the  use  of  this  book  the  topical 
method  of  recitation  should  be  adopted.  So  far  as 
possible,  the  order  of  the  subjects  is  uniform — viz.,  SOURCE, 
PREPARATION,  PROPERTIES,  USES,  and  COMPOUNDS.  The 
subject  of  each  paragraph  indicates  a  question  which  should 
draw  from  the  pupil  the  substance  of  what  follows.  At  each 
recitation  the  scholar  should  be  prepared  to  explain  any 
point  passed  over  during  the  term,  on  the  mention  of  its  title 
by  the  teacher.  Such  reviews  are  of  incalculable  value. 
While  some  are  reciting,  let  others  write  upon  specified 
topics  at  the  blackboard,  after  which  the  class  may  criticise 
the  thought,  the  language,  the  spelling,  and  the  punctua- 
tion. Never  allow  a  pupil  to  recite  a  lesson,  or  answer  a 
question,  except  it  be  a  mere  definition,  in  the  language  of 
the  book.  The  text  is  designed  to  interest  and  instruct  the 
pupil ;  the  recitation  should  afford  him  an  opportunity  of 
expressing  what  he  has  learned,  in  his  own  style  and  words. 
Every  pupil  should  keep  a  lecture-book,  in  which  to  record 
under  each  general  head  of  the  text-book  all  the  experi- 
ments, descriptions,  and  general  information  given  by  the 
teacher  in  class.  In  order  to  accustom  the  scholar  to  the 
nomenclature,  use  the  symbols  constantly  from  the  begin- 
ning :  they  may  seem  dull  at  first,  but  if  every  compound 
be  thus  named,  a  familiarity  with  chemical  language  will  be 
induced  that  will  be  as  pleasing  as  it  will  be  profitable.  If 
time  will  admit,  in  addition,  have  weekly  essays  prepared 
by  the  class,  combining  information  from  every  attainable 
source. 


Xll  SUGGESTIONS     TO     TEACHERS. 

Ocular  demonstration  is  absolutely  necessary  to  any 
progress  in  the  study  of  chemistry.  Simple  directions  with 
regard  to  the  experiments  are  given  in  the  Appendix  (see 
page  245)  which  will  enable  the  unprofessional  chemist  to 
perform  them  readily,  and,  in  case  it  is  convenient  for  the 
pupils  to  work  in  the  laboratory,  will  guide  them  in  their 
investigations.  The  subject  of  Qualitative  Analysis  is  also 
explained  so  clearly,  and  the  directions  are  so  complete 
(see  page  268),  that  even  the  amateur  student  can  grasp  the 
subject  and  demonstrate  its  principles. 

Teachers  desiring  pleasant  information  to  relieve  the 
recitation  hour,  will  find  it  in  that  delightful  work  of  Dr. 
Nichols,  Fireside  Science.  Many  curious  and  entertaining 
stories  and  facts  are  given  in  a  book  entitled  Treasures  of 
the  Earth.  For  a  common  work  of  reference,  Miller's  Ele-* 
ments  of  Chemistry,  3  vols.  octavo,  will  be  most  generally 
useful.  These  books  may  be  obtained  of  the  publishers  of 
this  series. 


TABLE  OF  CONTENTS. 


I.  — INTRODUCTION. 

PAGE 

DEFINITIONS 17 

NOMENCLATURE 19 

ATOMIC   THEORY 21 

ACIDS,  BASES,  AND   SALTS 22 

MATHEMATICS  OF  CHEMISTRY 24 


II.— INORGANIC    CHEMISTRY. 

1.— THE  NON-METALLIC   ELEMENTS. 

OXYGEN,  Ozone  and  Antozone 27 

NITROGEN,  Nitric  Acid,  Nitrous  Oxide,  etc 41 

HYDROGEN,  Water,  etc 50 

CARBON,  Carbonic  Acid,  Coal-Gas,  Combustion,  the  Atmos- 
phere, etc 64 

CHLORINE,  Hydrochloric  Acid,  etc 102 

IODINE 107 

BROMINE 106 

FLUORINE 106 

BORON 108 

SILICON,  Glass,  etc 109 

SULPHUR,  Sulphuric  Acid,  etc 113 

PHOSPHORUS,  Matches,  etc 119 

ARSENIC 123 

2.— THE   METALS. 

POTASSIUM 126 

SODIUM,  Common  Salt,  etc 130 

AMMONIUM 134 

CALCIUM 136 

STRONTIUM  AND  BARIUM -140 


XVI  TABLE     OF     CONTENTS. 

THE   METALS—  Continued.  PAGE 

MAGNESIUM 141 

ALUMINUM,  Ctay ? 143 

IRON 148 

ZINC 156 

TIN 157 

COPPER 158 

LEAD 159 

GOLD 162 

SILVER,  Photography,  etc 164 

PLATINUM 169 

MERCURY,  Mirrors,  etc 170 

THE  ALLOYS 172 

III.  — ORGANIC    CHEMISTRY. 

INTRODUCTION 181 

STARCH,  WOODY  FIBRE,  AND  SUGAR 184 

FERMENTATION,  Beer,  Wine,  Vinegar,  Alcohol,  etc 192 

ORGANIC  RADICALS 200 

DESTRUCTIVE  DISTILLATION,  Petroleum,  etc 204 

ORGANIC  ACIDS 210 

ORGANIC  BASES 212 

ORGANIC  COLORING  PRINCIPLES 216 

THE  OILS  AND  FATS 218 

RESINS  AND  BALSAMS 225 

ALBUMINOUS  BODIES" 228 

DOMESTIC  CHEMISTRY 232 

CONCLUSION,    Chemistry  of   the    Sunbeam,    Circulation    of 

Matter 237 

IV.  — A  P  P  E  N  D  I  X. 

1.  THE  NAMES  OF  CHEMICALS  ACCORDING  TO  THE  OLD  AND 

THE  NEW  NOMENCLATURE 243 

2.  SIMPLE  DIRECTIONS  CONCERNING  THE  EXPERIMENTS 245 

3.  CHEMICAL  ANALYSIS 268 

4.  QUESTIONS  FOR  CLASS  USE 279 

5.  LIST  OF  APPARATUS  AND  CHEMICALS 296 

6.  INDEX 298 


I. 

Jntrobuction. 


"  DEAD  mineral  matter,"  as  we  commonly  call  it,  is  instinct 
with  force.  Each  tiny  atom  is  attracted  here,  repelled  there, 
holds  and  is  held  as  by  bands  of  iron.  No  particle  is  left  to 
itself,  but,  watched  by  the  Eternal  Eye  and  guided  by  the  Eter- 
nal Hand,  all  obey  immutable  law.  When  Christ  declared  the 
>rery  hairs  of  our  head  to  be  numbered,  he  intimated  a  chemical 
'ruth,  which  we  can  now  know  in  full  to  be,  that  the  very  atoms 
of  which  each  hair  is  composed  are  numbered  by  that  same 
watchful  Providence. 


ELEMENTS  OF  CfEif'lSTRY. 


INTRODUCTION. 

Chemistry  treats  of  the  composition  of  bodies  and 
the  specific  properties*  of  matter. — Examples:  water 
consists  of  two  gases,  hydrogen  and  oxygen;  gold  is 
yellow. 

Organic  Chemistry  deals  with  those  substances 
which  have  been  produced  by  life. — Examples  :  flesh  and 
wood.  Inorganic  Chemistry  is  confined  to  those 
which  have  not  been  formed  by  life. — Examples :  sand, 
glass,  metals. 

An  Element  is  a  kind  of  matter  which  has  never 
been  separated  into  other  substances. — Examples:  gold, 
iron.  Sixty-three  elements  are  now  known,  \  fifty  of 
which  are  considered  as  metals  and  thirteen  as  non-metals. 

Chemical  Affinity  is  that  force  which  causes  the 
elements  of  matter  to  unite  and  form  new  compounds. 
It  acts  at  distances  so  slight  as  to  be  insensible,  and  upon 
the  most  dissimilar  substances :  the  more  dissimilar,  the 

*  See  Fourteen  Weeks  in  Natural  Philosophy,  pages  14,  15. 

t  Though  there  has  been  no  element  discovered  for  the  past  seven  years,  it  is 
not  probable  that  the  list  is  complete.  However,  we  cannot  suppose  that  any 
element  very  abundant  in  the  earth's  crust  is  yet  to  be  found.  Indeed,  of  the 
thirty-two  made  known  since  1774  (the  year  of  the  discovery  of  O,  Cl,  etc.),  the 
great  majority  have  been  only  chemical  curiosities.— The  division  into  metals 
and  non-metals  is  an  arbitrary  one,  and  not  fully  established.  (See  note,  p.  123.) 


18  ELEMENTS     OF    CHEMISTRY. 

stronger  the  union. — Example :  a  little  potassium  ehlo- 
*  vandjsul|)}iui'  mixed  in  a  mortar  will  not  combine, 
a  slight 'pressure  of  the  pestle  will  bring  them  within 
4h£  i-ahge  pf  attraction,  when  they  will  burn  with  a  loud 
Explosion.-  N-c thing ^iii  the  nature  or  appearance  of  an  ele- 
ment indicates  its  chemical  affinity,  and  it  is  only  by  trial 
that  we  can  tell  with  what  it  will  combine.  This  attraction 
is  not  a  mere  freak  of  nature,  but  a  force  imparted  to 
matter  by  God  himself  for  wise  and  beneficent  purposes. 

Compounds,  in  their  properties,  are  in  general  very 
unlike  their  elements. f — Examples  :  yellow  sulphur  and 
white  quicksilver  form  red  vermilion ;  inert  charcoal, 
hydrogen,  and  nitrogen  produce  the  deadly  prussic  acid ; 
solid  charcoal  and  sulphur  make  a  colorless  liquid ;  poi- 
sonous and  offensive  chlorine  combines  with  the  brilliant 
metal  sodium  to  form  common  salt. 

Heat  and  .Light  favor  chemical  action,  and  fre- 
quently develop  an  affinity  where  it  seemed  to  be  wanting. 
The  former  especially,  by  its  expansive  force,  tends  to 
drive  the  elements  of  a  compound  without  the  range  of 
old  attractions  and  within  that  of  new  ones. — Examples  : 
gun-cotton,  when  lying  in  the  air,  is  apparently  harm- 
less, but  a  spark  of  fire  will  produce  a  brilliant  flash,  and 
cause  it  to  disappear  as  a  gas :  nitrate  of  silver  in  contact 
with  organic  matter  turns  black,  by  the  action  of  the  light. 

Solution  also  aids  in  chemical  change,  as  it  destroys 
cohesion  and  leaves  the  atoms  free  to  unite. — Example  : 
sodium  carbonate  \  and  tartaric  acid '  mixed  in  a  glass 

*  "  Chlorate  of  potash." 

t  "The  elements  have  no  more  likeness  to  the  compounds  which  they  form 
than  the  separate  letters  of  the  alphabet  have  to  the  words  which  may  be  made 
from  them.1" — MILLER. 

±  "  Carbonate  of  soda." 


INTRODUCTION.  19 

will  not  combine,  but  the  addition  of  water  will  cause  a 
violent  effervescence. 

Nomenclature. — The  elements  which  were  known 
anciently  retain  their  former  names.  Those  discovered 
more  recently  are  named  from  some  peculiarity. — Exam- 
ples :  chlorine,  from  its  green  color ;  bromine,  from  its 
bad  odor.  The  uniform  termination  um  has  been  given 
to  the  lately  found  metals.  —  Examples:  potassium, 
sodium.  A  similarity  of  ending  in  non-metallic  elements 
indicates  some  analogy.  —  Examples:  silicon,  boron; 
iodine,  bromine. 

Symbols.  —  For  the  sake  of  brevity  chemists  use  a 
kind  of  short-hand.  The  first  letter  of  its  English  name 
is  generally  taken  as  the  symbol  of  an  element.  When 
that  would  produce  confusion,  the  Latin  initial  is  sub- 
stituted, and  in  some  cases  a  second  letter  added. — Ex- 
amples: carbon  and  chlorine  both  commence  with  C; 
so  the  latter  takes  Cl  for  its  symbol.  Silver  and  silicon 
both  begin  with  Si,  hence  the  former  assumes  Ag,  from 
its  Latin  name,  Argentum.  If  more  than  one  atom  of  an 
element  be  used  in  forming  a  molecule  of  a  compound, 
this  is  shown  by  writing  the  number  below  the  symbol. — 
Example:  H20  indicates  that  in  a  molecule  of  water 
there  are  two  atoms  of  hydrogen  and  one  of  oxygen. 

The  JLtomic  Weigfil  of  an  element  expresses  the 
proportion  by  weight  in  which  it  unites  with  other  ele- 
ments. There  is  no  chance-work  in  nature.  No  matter 
under  what  circumstances  a  compound  is  formed,  the 
proportion  of  its  elements  is  the  same. — Example :  the 
carbonic  acid  produced  amid  the  roar  of  a  conflagration 
or  the  explosion  of  a  volcano  is  identical  witli  that  made 
in  the  quiet  burning  of  a  match. 


ELEMENTS     OF    CHEMISTRY. 


In  the  following  table  are  given  the  symbols  of  the 
elements  and  their  atomic  weights.  The  most  important 
elements  are  printed  in  capitals,  those  of  less  conse- 
quence in  italics,  and  rare  ones  in  ordinary  type.  It  will 
be  seen  that  hydrogen  is  taken  as  the  unit  of  atomic 
weight. 

ELEMENTS  WITH  THEIR   SYMBOLS  AND  ATOMIC  WEIGHTS. 

(Tomlinsori >s  MUler's  Chemistry,  1871.) 


Name 

Symbol 

Atomic 
Weight 

Name 

Symbol 

Atomic 
Weight 

ALUMINUM 

Al 

27.5 

Molybdenum  . 

Mo 

96 

Antimony  (Stibium) 

Sb 

122 

Nickel 

Ni 

59 

Arsenic 

As 

75 

Niobium 

Nb 

94 

BARIUM 

Ba 

137 

NITROGEN 

N 

14 

Bismuth 

Bi 

210 

Osmium 

Os 

199 

Boron 

B 

11 

OXYGEN 

0 

16 

Bromine 

Br 

80 

Palladium 

Pd 

106 

Cadmium 

Cd  ' 

112 

PHOSPHORUS  . 

P 

31 

Caesium 

Cs 

133 

Platinum 

Pt 

197 

CALCIUM 

Ca 

40 

POTASSIUM    (Ka-  ) 

OQ 

CARBON 

C 

12 

lium)   .        .       f 

Oo 

Cerium 

Ce 

92 

Rhodium 

Ro 

104 

CHLORINE 

Cl 

35.5 

Rubidium 

Rb 

85 

Chromium 

Cr 

52.5 

Ruthenium     . 

Ru 

104 

Cobalt 

Co 

59 

Selenium 

Se 

79.5 

COPPER  (Cuprum)  . 

Cu 

63.5 

SILICON          .       . 

Si 

28 

Didymium 

D 

96 

SILVER  (Argentum) 

Ag 

108 

Erbium 

E 

112 

SODIUM    (Natrium) 

Na 

23 

Fluorine 

F 

19 

Strontium 

Sr 

87.5 

Glucinum 

G 

9.5 

SULPHUR 

S 

32 

Gold  (Aurum) 

Au 

197 

Tantalum 

Ta 

182 

HYDROGEN 

H 

1 

Tellurium 

Te 

129 

Indium 

In 

76 

Thallium 

Tl 

204 

Iodine 

I 

127 

Thorium 

Th 

238 

Iridium 

Ir 

197 

Tin  (Stannum) 

Sn 

118 

IRON  (Ferrum) 

Fe 

56 

Titanium 

Ti 

50 

Lanthanum 
LEAD  (Plumbum)  . 
Lithium 

La 
Pb 
L 

92 

207 

7 

Tungsten    (  Wol  -  ) 
framium)    .       J 
Uranium 

W 

U 

184 
120 

MAGNESIUM    . 

Mg 

24 

Vanadium 

V 

51 

MANGANESE   . 

Mn 

55 

Yttrium 

Y 

62 

MERCURY      (Hy  -  ) 
drargyrum)  .       j 

Hg 

200 

ZINC 
Zirconium 

Zn 
Zr 

65 

89 

INTRODUCTION.  21 

The  Atomic   Theory*  which  lies  at  the  basis  of 
chemistry,  as  now  understood,  supposes  : 

1.  That  each  element  is  composed  of  indivisible  atoms 
which  are  exactly  equal  in  size  and  weight. 

2.  That  the  atomic   weights    represent    the    relative 
weights  of  the  atoms  of  various  kinds. 

3.  That  compounds  are  formed  by  the  union  of  atoms 
of  different  kinds  in  the  proportion  of  their  atomic 
weights  or  multiples  of  them. 

4.  That  the   molecular  weight  f    of   a   compound   is 
equal  to  the  sum  of  the  atomic  weights  of  its  elements. 

A  ^Binary  Compound  is  a  union  of  two  elements. 
In  writing  its  symbol,  we  place  first  that  of  the  electro- 
positive, \  and  then  that  of  the  electro-negative  element. 
In  writing  the  name,  or  in  reading  the  symbol,  the  latter 
element  takes  the  termination  ide.  Thus  potassium  and 
iodine  form  the  compound  which  is  written  KI,  and  read 
potassium  iodide ;  sodium  and  chlorine,  NaCl,  sodium 
chloride;  zinc  and  oxygen,  ZnO,  zinc  oxide. § 

One  atom  of  0  in  a  molecule  forms  the  monoxide  or 
protoxide,  two  the  dioxide  or  binoxide,  three  of  0  and 
two  of  the  other  element,  the  sesquioxide  (meaning  1J), 
and  the  highest  number,  the  peroxide.  Thus, 


*  See  Philosophy,  page  19. 

t  By  molecular  weight  is  meant  the  weight  of  the  smallest  particle  of  the 
compound  which  can  exist  in  a  separate  form.  (See  Philosophy,  page  21.) 

J  See  Philosophy,  page  298. 

§  There  are  three  variations  from  this  statement  which  should  be  noticed. 
1.  Many  chemists  give  the  electro-positive  element  the  termination  ic,  thus  read- 
ing KI,  potassic  iodide.  2.  The  electro-negative  element  is  often  read  first, 
and  the  word  of  placed  between  the  elements  ;  thus  KI  is  called  the  iodide  of 
potassium.  3.  In  the  case  of  phosphorus,  carbon,  and  sulphur,  the  termination 
uret  is  sometimes  used  instead  of  ide  ;  thus  FeS  is  read  the  eulphuret  of  iron, 
instead  of  iron  (ferrous)  sulphide  or  the  sulphide  of  iron. 


%%  ELEMENTS     OF    CHEMISTRY. 

N20  =  Nitrogen  Monoxide  (protoxide), 

N.202  =         "          Dioxide  (binoxide), 

N203  =         "          Trioxide, 

N204  =         "          Tetroxide, 

N2O5  =          "          Pentoxide. 

oicids,  Bases,  and  Salts.—  There  are  two  large 
classes  of  oxides  chemically  opposed  to  each  other,  termed 
adds  and  bases  ;  their  compounds  are  called  salts. 

The  jLcids  are  generally  sour  *  and  turn  vegetable 
colors — such  as  the  infusion  of  blue  litmus,  or  of  purple 
cabbage  f — to  a  bright  red.  They  are  named  from  the 
elements  with  which  0  combines.  The  termination  indi- 
cates the  amount  of  0, — ic  representing  the  greater,  and 
ous  the  lesser. — Example:  sulphur  forms  two  acids  of 
different  strength — sulphuric,  the  stronger,  and  sulphur- 
ous, the  weaker.  If  an  acid  has  been  afterwards  found 
containing  more  0  than  the  stronger,  it  takes  the  prefix 
ger  ;  one  having  less  than  the  weaker,  the  prefix  hypo. — 
Example :  chlorine  combines  with  oxygen  and  hydrogen 
to  form  a  series  of  acids  in  regular  gradation. 

Hypochlorous  Acid  HCiO, 
Chlorous    "      HCIO.,, 
Chloric       "      HCIO  3, 
Perchloric        "      HC104. 

Hydrogen  by  its  union  with  different  elements  forms 
acids  which  contain  no  0.  These  combine  the  names  of 


*  Certain  acids,  as  well  as  certain  bases,  are  insoluble  in  water,  and  hence 
have  no  taste.  They,  however,  combine  to  form  salts,  which  is  their  true  test. 

t  Paper  tinged  blue  with  a  solution  of  litmus  (a  coloring  matter  obtained  from 
certain  lichens)  should  be  constantly  at  hand  in  the  laboratory,  to  determine  the 
presence  of  a  free  acid.  The  same  paper  faintly  reddened  by  vinegar,  or  any 
other  acid,  is  a  convenient  test  for  the  alkalies.  The  cabbage  solution  is  made 
by  steeping  red  cabbage-leaves  in  water,  and  straining  the  purplish  liquid  thus 
obtained. 


INTRODUCTION.  .  23 

both  elements. — Example:  hydrogen  and  chlorine  form 
hydrochloric  acid. 

The  XBases  are  commonly  oxides  of  the  metals.  Their 
termination,  as  in  the  acids,  indicates  the  amount  of  oxy- 
gen. Thus  mercury  has  two  oxides,  HgO  and  Hg20, 
termed  respectively  mercuric  oxide  and  mercurous  oxide ; 
iron  forms  FeO,  ferrous,  and  Fe203,  ferric  oxide.  The 
alkalies*  are  bases  which  are  soluble  in  water,  have  a 
soapy  taste  and  feel,  turn  red  litmus  to  blue,  and  red- 
cabbage  solution  to  green,  neutralize  the  acids  and  re- 
store the  colors  changed  by  them.  The  property  which 
the  acids  and  bases  thus  have  of  uniting  with  each  other 
and  destroying  the  chemical  activity  which  either  possesses 
alone,  is  their  distinguishing  trait. \ 

The  SctUs  are  compounds  formed  by  the  union  of  an 
acid  and  a  base.J  In  naming  a  salt,  the  termination  of 
the  acid  is  changed — an  ic  acid  forming  an  ate  compound, 
and  an  ous  acid  an  ite  compound.  Thus  the  salts  of  sul- 
phuric acid  are  called  sulphates,  and  of  sulphurous  acid, 
sulphites ;  of  nitric  acid,  nitrates,  and  of  nitrous  acid,  ni- 
trites. Sulphuric  acid  combining  with  ferrous  oxide  forms 
ferrous  sulphate,  and  with  ferric  oxide,  ferric  sulphate. 

A  Formula  is  an  algebraic  statement  of  the  sym- 
bols and  relations  of  several  compounds.  The  sign  +  in- 

*  The  alkalies  are  compounds  of  H,  O  and  a  metal.  They  are  hence  called  hy- 
droxides :  as  KHO  (potassium  hydrate,  caustic  potash),  NaHO  (sodium  hydrate). 

t  To  a  part  of  the  purple-cabbage  solution  add  a  few  drops  of  a  solution  of 
caustic  potash :  a  green  liquid  will  be  produced.  To  another  portion  add  a  few 
drops  of  sulphuric  acid:  the  solution  will  become  red.  Pour  the  red  acid  liquor 
into  the  green  alkaline  one,  and  stir  the  mixture :  the  red  color  at  first  disap- 
pears, and  the  whole  remains  green ;  but  on  adding  it  cautiously,  a  point  is 
reached  at  which  it  assumes  a  clear  blue  color.  There  is  then  no  excess  of  acid 
or  alkali ;  and  on  evaporation,  a  neutral  salt,  potassium  sulphate,  may  be  obtained. 

%  We  shall  come  hereafter  to  substitute  for  this  simple  definition  the  more 
exact  chemical  one,  that  a  salt  is  an  acid  in  which  one  or  more  atoms  of  H  have 
been  replaced  by  a  metal.  (See  note,  p.  44 ;  reaction,  p.  51 ;  and  notes,  p.  128.) 


%4  ^ELEMENTS     OF     CHEMISTRY. 

dicates  a  feeble  attraction  or  a  mere  mixture.  The  sign 
=  indicates  conversion  into.  The  comma  or  the  period 
denotes  a  combination.  The  brackets  and  coefficients  are 
used  as  in  algebra. 

Mathematics  of  Chemistry.  —  There  is  a  Divine 
law  of  harmony  which  runs  like  a  golden  thread  through 
all  nature,  giving  always  unity  and  completeness.  Its 
beauty  and  simplicity  are  nowhere  seen  more  clearly 
.than  in  the  law  of  atomic  weights.  Applying  the  fourth 
principle  of  the  atomic  theory,  we  see  that  the  atomic 
weight  of  any  element  in  a  compound,  divided  by  the 
molecular  weight  of  that  compound,  is  the  proportion  of 
that  element  contained  in  it.  —  Example  :  the  molecular 
weight  of  water,  H20,  is  2  +  16=18;  hence  the  propor- 
tion of  H  is  T2g  or  £,  and  of  0,  }|  or  f  .  In  10  Ibs.  of 
"H20,  there  are  therefore  10  xf  or  8f  Ibs.  of  0,  and 
10  xj  or  1^  Ibs.  of  H.* 

Apply  this  principle  to  the  solution  of  the  following 

PROBLEMS. 

1.  In  a  25-lb.  sack  of  table  salt  (NaCl,  sodium  chloride),  how  many 
Ibs.  of  the  metal  sodium  ?  f 

2.  In  14  Ibs.  of  iron-rust  (Fe2O:J),  how  much  0  ? 

3.  How  much  S  is  there  in  2  Ibs.  of  S02  ? 

4.  How  much  S  is  there  in  2  Ibs.  of  H2S04  (sulphuric  acid)? 

5.  How  much  0  is  there  in  5  Ibs.  of  HN03  (nitric  acid)? 

6.  How  much  H  is  there  in  6  Ibs.  of  HC1  (hydrochloric  acid)  ? 

7.  How  much  potash  (K20)  could  be  made  from  3  Ibs.  of  potas- 


* This  may  also  be  solved  by  the  following  proportion  :— 
The  atomic  weight  of  an  element  :  molecular  weight  of  a  compound  :  :  weight 
of  the  element  :  weight  of  the  compound. 
2  :  18  :  :  *  :  10  Ibs.    x=l£  Ibs.  (H). 
16  :  18  :  :  X  :  10  Ibs.    a:=85  Ibs.  (O). 
t  23  :  58  5  :  :  x  :  25  Ibs.     ar=9r9TV  Ibs.  (Na). 
$  78  :  94  :  :  3  Ibs.  :  x.    x^&&  Ibs.  (KaO). 


1 1. 

3norgamc   Chemistry. 


"  IN  the  de-oxidation  and  re-oxidation  of  the  hydrogen  in  a 
single  drop  of  water,  we  have  before  us,  so  far  as  force  is  con- 
cerned, an  epitome  of  the  whole  of  life." — HINTON. 


INORGANIC    CHEMISTRY, 


THE     NON-METALS. 
OXYGEN. 

Symbol,  0 Atomic  Weight,  16 Specific  Gravity,  1,1, 

THE  name  Oxygen  means  acid-former,  and  was  given 
because  it  was  supposed  to  be  the  essential  principle  of 
all  acids ;  but  hydrogen  has  since  been  found  to  be  the 
true  acid-maker. 

Fig.  3. 


Collecting  O  over  a  pneumatic  tvb, 


28  INORGANIC     CHEMISTRY. 

Source. — 0  is  the  most  abundant  of  all  the  elements — 
comprising  by  weight  \  of  the  air,  f  of  the  water,  |  of 
all  animal  bodies,  and  about  \  of  the  crust  of  the  earth. 

Preparation. — The  simplest  method  of  preparing  0  for 
experimental  purposes  is  to  heat  a  mixture  of  potassium 
chlorate  (KC103)  and  manganese  dioxide  (Mn02)*  in  a 
flask,  and  collect  the  gas  over  a  pneumatic  tub,  as  in  the 
accompanying  illustration.! 

The  ^Reaction,  chemical  change,  is  as  follows : 


2  KC10 


2  KC1  + 


Two  molecules  of  potassium  chlorate  are  converted  into 
two  of  potassium  chloride  and  six  atoms  of  0,  which  pass 
oif  as  a  gas.  The  reaction  may  also  be  represented  thus : 

(Potassium  Chlorate)          (Potassium  Chloride)       (Oxygen) 

2  K     Cl      03  =        2K      Cl         +          06 

2(39  +  35.5  +  3x16)  2(39  +  35.5)  6x16 


245  149  96 


The  0  set  free  will  be  equal  to  -f^  of  the  potassium 
chlorate  used,  i.  e.,  every  245  parts  by  weight  (grs.,  oz., 
or  Ibs.)  will  yield  96  parts  (grs.,  oz.,  or  Ibs.)  of  0,  and 
149  parts  (grs.,  oz.,  or  Ibs)  of  KCL 

A  Curious  Fact  appears  in  this  process.  If  the 
KC103  were  heated  alone,  a  very  high  temperature  would 

*  This  substance  is  commonly  known  as  binoxide  of  manganese,  and,  because 
of  its  color,  the  black  oxide  of  manganese. 
t  See  Appendix  for  directions  in  performing  this  and  other  experiments. 


OXYGEN.  29 

be  necessary,  which  would  liberate  the  gas  rapidly,  and 
often  with  explosive  violence.  If,  however,  we  mix  with 
it  a  little  manganese  dioxide,  the  gas  will  be  set  free  at  a 
much  lower  temperature,  and  may  be  regulated  so  as  to 
come  off  a  bubble  at  a  time.  At  the  conclusion  of  the 
process,  the  Mn02  will  be  found  unchanged.  The  reason 
of  this  wonderful  action  is  beyond  our  comprehension. 
The  influence  of  one  body  over  another,  by  its  mere 
presence,  is  called  catalysis. 

Properties. — 0  has  no  odor,  color,  or  taste.  It  com- 
bines with  every  element  except  fluorine.  From  some  of 
its  compounds  it  can  be  set  free  by  the  stroke  of  a  ham- 
mer, while  from  others  it  can  be  liberated  only  by  the 
most  powerful  means.  Its  union  with  a  substance  is 
called  oxidation,  and  the  product  an  oxide.  It  is  a  vigor- 
ous supporter  of  combustion. 

The  following  experiments  will  illustrate  its  chemical 
energy. 

1.  By  blowing  quickly  up- 
ward upon  a  candle,  extinguish 
the  flame,  and  leave  a  glowing 
wick.  If  this  be  plunged  into 
a  jar  of  0,  the  coal  will  burst 
into  a  brilliant  blaze.  The 
experiment  may  be  repeated 
many  times  before  the  0  will 
be  exhausted.  A  new  colorless  A  candle  in  o. 

gas,  CO  2?  called  carbonic  anhy- 
dride* (" carbonic  acid")  is  formed  by  the  combustion. 

*  An  anhydride  (without  hydrogen)  is  a  substance  which,  when  dissolved  in  HaO 
will  unite  with  its  elements  and  form  an  acid.  It  is  then  strictly  a  salt  in  which 
H  plays  the  part  of  a  base,  and  is  called  -a  hydride.  In  this  state  only  is  it 


SO- 


INORGANIC     CHEMISTRY. 


•  2.  Straighten  a  watch-spring 
by  drawing  it  between  the  fin- 
gers. Pass  one  end  through  a 
cork,  heat  the  other  slightly 
and  dip  it  into  powdered  sul- 
phur. Light  this  and  plunge 
it  into  a  jar  of  0,  holding  it  in 
the  neck  by  the  cork.  The 
burning  sulphur  will  ignite  the 
steel,  which  will  burn  with  a 
shower  of  fiery  stars,  while  melted  globules  of  the  black 
oxide  of  iron  (Fe304)  will  fall  upon  the  plate  below. 

3.  Ignite  a  bit  of  sulphur  placed 
on  a  stand,  and  invert  over  it  a 
jar  of  0  J  it  will  burn  with  a  beau- 
tiful blue  light,  and  the  fumes  of 
sulphurous  anhydride,  S02?  ("sul- 
phurous acid  ")  will  circle  about  the 
receiver  m  curious  concentric  rings. 
The  gas  has  a  pungent  odor,  and 
will  be  absorbed  by  the  water  on 
the  plate,  where  it  may  be  tested. 
4.  Place  in  the  bottom  of   a  "  deflagrating  spoon," 
(see  Appendix,  p.  249)  a  little  fine,  dry  chalk;  then -wipe 
a  bit  of  phosphorus,  about  the  size  of  a  pea,  very  care- 
fully and  quickly  between  pieces  of  blotting-paper ;  lay 
this  upon  the  chalk,  and,  holding  the  spoon  over  a  large 


A  watch-spring  in  O. 


Fig.  5. 


Sulphur  in  O. 


properly  termed  an  acid.  The  two  compounds  are  frequently  distinguished  as 
anhydrous  (without  water),  and  hydrated  (with  water).  Until  of  late  it  has 
been  customary  to  apply  the  term  acid  to  either  form.  Thus  COa  (carbon  di- 
oxide) is  strictly  carbonic  anhydride,  but.  has  been  so  long  knowr>  as  carbonic 
acid  that  its  proper  appellation  is  rarely  used.  The  same  is  tone  o*  ' 
named  in  the  3d.  and  4th.  experiments. 


81 


Phosphorus  in  O.    "  The  phosphoric  sun" 

jar  'of  0,  ignite  the  phosphorus  with  a  heated  wire,  and 
lower  it  steadily  into  the  gas.  The  phosphorus  will 
burst  into  a  flood  of  blinding  light,  while  dense  fumes  of 
phosphoric  anhydride,  P205,  ("phosphoric  acid")  will 
roll  down  the  sides  of  the  jar. 

5.  Make  a  little  tassel  of  zinc-foil,  tip  the  ends  with 
sulphur  as  in  the  3d  experiment,  ignite  and  lower  into  a 
jar  of  0.    It  will  burn  with  a  dazzling  light,  forming  zinc 
oxide  (ZnO). 

6.  If  a  piece  of  charcoal-bark  be  ignited  and  lowered 
into  a  jar  of  0,  it  will  deflagrate  with  bright  scintilla- 
tions. 

The  1)estritctive  Agent  of  the  Mr.  — 0  is  the 
active  principle  of  the  atmosphere.  Comprising  one-fifth 
of  the  common  air,  it  is  ever-present,  and  ever-waiting. 
We  gather  a  basket  of  peaches  and  set  them  aside.  In  a 
short  time,  black  spots  appear,  and  we  say  they  are  decay- 


32  INORGANIC    CHEMISTRY. 

ing.  It  is  only  the  0  corroding  them,  i.  e.,  breaking  up 
their  chemical  structure  to  form  new  and  unpleasant 
compounds.  To  prevent  this  action,  we  place  the  fruit 
in  a  can,  heat  it  to  expel  the  0,  and  seal  it  tightly. — We 
open  the  damper  of  the  stove  and  the  air  rushes  in.  The 
0  immediately  attacks  the  heated  fuel.  Every  two  atoms 
combine  with  an  atom  of  C  and  fly  off  into  the  air  as  C02- 
— We  cut  a  finger,  and  soon  feel  the  0  at  work  upon  the 
quivering  nerve  beneath.  We  apply  a  strip  of  "court- 
plaster"  to  keep  out  the  air  and  give  nature  an  oppor- 
tunity to  heal  the  wound.* — Our  teeth  decay  only  because 
of  the  action  of  the  0.  The  dentist  saves  them  by  filling 
any  break  in  the  enamel  with  a  cement  which  is  already 
oxidized,  or  with  a  metal,  as  Au  or  Pt,  which  has  little 
affinity  for  0. — The  H20  in  the  cistern  becomes  foul  and 
putrid.  We  uncover  it ;  in  rushes  the  0,  picks  up  each 
atom  of  impurity,  and  sinks  to  the  bottom.  The  thick 
sediment  we  find  when  it  is  cleaned  in  the  spring,  is  but 
the  ashes  of  this  combustion,  f — The  blacksmith  draws  a 
red-hot  iron  from  his  forge.  While  the  metal  is  glowing, 
the  0  forms  scales  of  the  black  oxide  of  iron  (Fe304.), 
which  fly  blazing  in  every  direction.  J — We  wipe  our  knives 


*  The  treatment  of  a  burn  as  well  as  a  cut  consists  in  the  immediate  exclusion 
of  the  air.  It  is  a  mistake  to  suppose  that  a  salve  will  "draw  out  the  fire1' 
of  a  burn,  or  heal  a  bruise  or  cut.  The  vital  force  must  unite  the  divided  tissue 
by  the  deposit  of  material,  and  the  formation  of  new  cells.  (Physiology,  p.  205.) 

t  "  As  the  vessel  sets  sail  from  London,  the  captain  fills  the  water-casks  with 
water  from  the  River  Thames,  foul  with  the  sewage  of  the  city,  and  containing  23 
different  species  of  animalcules ;  yet,  in  a  few  days,  the  O  contained  in  the  air 
dissolved  by  the  H2O,  will  have  cleansed  it,  and  the  HaO  will  be  found  sweet 
and  wholesome  during  the  voyage." 

$  Quite  in  contrast  to  this  pyrotechnic  display  is  the  action  of  the  O  upon  the 
Fe  contained  in  writing-fluid.  At  first  the  words  are  pale  and  indistinct,  but  in 
a  few  hours  the  O,  noiselessly  combining  with  the  metal  (see  p.  212),  brings  out 
every  letter  in  clear,  bold  characters  upon  the  page. 


OXYGEN.  S3 

and  forks,  and  lay  them  carefully  away ;  but  if  we  have 
left  on  them  a'  particle  of  moisture,  since  H20  favors 
chemical  change,  the  0  will  find  it,  and  corrode  the 
steel.*— An  animal  dies,  and  the  0  at  once  begins  to  re- 
move  the  body.  The  atoms  which  have  been  used  to 
perform  the  functions  of  life,  are  separated  by  the  0,  and 
set  at  liberty  to  enter  into  new  combinations. 

0  in  the  JZuman  System. — We  take  the  air  into 
our  lungs.  Here  the  blood f  absorbs  the  0,  and  bears  it 
to  all  parts  of  the  body,  depositing  it  wherever  it  is 
needed.  Laden  with  this  life-giving  element,  the  vital 
fluid  sweeps  tingling  through  every  artery  and  vein,  dis- 
tends each  capillary  tube,  sends  the  quick  flush  to  the 
cheek,  combines  with  a  portion  of  the  food  thrown  into 
the  circulation  from  the  stomach,  breaks  up  every  worn- 
out  tissue,  burns  up  the  muscles,  and  sets  free  their  force, 
until  at  last  it  comes  back  through  the  veins  dark  and 
thick  with  the  products  of  the  combustion — the  cinders 
of  the  fire  within  us. 

Combustion  and  Heat. — All  ordinary  processes 
of  fermentation,  decay,  putrefaction,  and  fire,  are  pro- 
duced by  a  union  of  0  with  a  substance,  and  are 
only  different  forms  of  oxidation.  They  differ  in  the 
time  employed  in  the  operation.  If  0  unites  rapidly, 


*  The  compound  here  formed  will  be  a  higher  oxide  than  that  produced  at  the 
blacksmith's  forge,  since  a  portion  of  the  O  which  there  united  with  the  iron 
was  driven  off  by  the  heat.  It  wiU  be  the  red  oxide  of  iron  (Fe2O3,  ferric  oxide), 
or  common  iron-rust,  as  we  see  it  on  stoves  and  other  utensils. 

+  The  blood  is  full  of  red  corpuscles  or  cells  containing  Fe.  These  are  so  tiny, 
that  a  million  of  them  cluster  in  the  drop  which  will  cling  to  the  point  of  a 
needle.  Quickly  assuming  a  tawny  hue,  like  the  decayed  leaves  of  autumn, 
they  change  so  rapidly  that  20,000,000  perish  with  every  breath.— DRAPER. 

These  cells  when  fresh  act  like  little  gas-bags  in  carrying  the  O  through  the 
body.  . 


34  INORGANIC    CHEMISTRY. 

we  call  it  fire-;  if  slowly,  decay.  Yet  the  process 
and  the  products  are  the  same.  A  stick  of  wood 
is  burned  in  the  stove,  and  another  rots  in  the 
forest,  but  the  chemical  change  is  identical.  In  the 
combination  of  an  atom  of  0,  a  certain  amount  of  heat 
is  produced.*  Hence,  the  house  that  decays  in  fifty 
years,  gives  out  as  much  heat  during  that  time  as  if 
it  had  been  swept  off  by  a  fierce  conflagration  in  as 
many  minutes. 

The  JTuman  Furnace .  —The  body  is  like  a  stove  in 
which  fuel  is  burned,  and  the  chemical  action  is  precisely 
like  that  in  any  other  stove.  This  combustion  produces 
heat,  and  our  bodies  are  kept  warm  by  the  constant  fire 
within  us.  We  thus  see  why  we  fortify  ourselves  against 
a  cold  day  by  a  full  meal.  When  there  is  plenty  of  fuel 
in  our  human  furnaces,  the  0  burns  that ;  but  if  there 
is  a  deficiency,  the'  destructive  0  must  still  unite  with 
something,  and  so  it  combines  with  the  'flesh ; — first  the 

*  "  Wlien  considerable  masses  of  iron  are  allowed  to  rust,  a  distinct  elevation 
of  temperature  is  often  perceived.  This  is  seen  when  a  heap  of  iron  turnings 
of  from  10  Ibs.  to  20  Ibs.  is  moistened*  with  water  and  exposed  to  the  air.  A 
curious  illustration  of  the  fact  was  afforded  during  the  manufacture  of  the  Medi- 
terranean Electric  Cable.  The  copper  conducting  wire  of  this  cable  was  coated 
with  gutta-percha ;  this  was  covered  with  a  serving  of  tar  and  hemp,  and  the  whole 
was  enclosed  in  a  strong  casing  of  iron  wire.  The  cable  as  it  was  manufactured 
was  coiled  in  tanks  filled  with  water.  These  tanks  leaked,  and  the  water  was 
therefore  drawn  off,  leaving  a  quantity  of  cable,  about  163  nautical  miles  in  length, 
coiled  into  a  mass  about  30  feet  in  diameter  with  an  eye  or  central  space  of  6 
feet ;  the  height  of  the  coil  was  about  8  feet.  Rapid  oxidation  took  place,  and 
the  temperature  at  the  centre  of  the  coil,  nearly  three  feet  from  the  bottom,  rose 
in  four  days  from  66°  to  79°,  although  the  temperature  of  the  air  did  not  exceed  66° 
during  the  period,  and  was  as  low  as  59°  part  of  the  time.  In  other  parts  of  the 
mass  the  heat  rose  so  high  as  to  cause  the  water  to  evaporate  sufficiently  rapidly 
to  produce  a  visible  cloud  of  vapor,  and  to  give  rise  to  apprehensions  that  the 
insulating  power  of  the  cable  would  be  destroyed  by  the  softening  of  the  gutta- 
percha.  No  doubt  the  rise  of  temperature  would  have  been  still  greater  had  it 
not  been  checked  by  the  affusion  of  cold  water ;  but  the  oxidation  and  the  heat- 
ing were  renewed  when  the  cooling  was  discontinued.  The  oxidation  occurred 
only  on  the  external  surface  of  the  iron  wires,  that  portion  in  contact  with  the 
tarred  hemp  remaining  perfectly  bright."— MILLER. 


OXYGEN.  3d 

fat,  and  the  man  grows  poor ;  then  the  muscles,  and  he 
grows  weak ;  finally  the  brain,  and  he  becomes  crazed. 
He  has  simply  burned  up,  as  a  candle  burns  out  to  dark- 
ness. 

0  'Produces  Motion.— As  soon  as  we  begin  to  per- 
form any  unusual  exercise,  we  commence  breathing  more 
rapidly,— showing  that,  in  order  to  do  the  work,  we"  need 
more  0  to  unite  with  the  food  *  and  muscles.  In  very  vio- 
lent labor,  as  in  running,  we  are  compelled  to  open  our 
mouths,  and  take  deep  inspirations  of  0.  This  increased 
fire  within  elevates  the  temperature  of  the  body,  and 
we  say  "  we  are  so  warm  that  we  pant."  Keally  it  is  the 
reverse.  The  panting  is  the  cause  of  our  warmth. 

During  sleep  the  organs  of  the  body  are  mostly  at  rest, 
except  the  heart.  To  produce  this  small  muscular  exer- 
tion very  little  0  is  required.  As  our  respiration  is,  there- 
fore, slight,  our  pulse  sinks,  the  heat  of  our  body  falls, 
and  we  need  much  additional  clothing  to  keep  warm.f 
Thus  we  require  0  not  only  to  keep  us  warm,  but  also  to 
do  all  our  work.  Cut  off  its  supply,  and  we  grow  cold ; 
the  heart  struggles  spasmodically  for  an  instant,  but  the 
motive  power  is  gone,  and  we  soon  die. 

JIow  0  gives  us  Strength .  —Our  muscles,  as  well 
as  the  food  from  which-  they  are  formed,  consist  of  com- 


*  It  is  probable  that  a  portion  of  our  food,  especially  the  carbonaceous,  is  oxi- 
dized directly  without  becoming  an  integral  part  of  the  body.  The  heat  thus  set 
free  by  the  principle  of  the  correlation  of  force  (see  Physiology,  page  134),  may  be 
converted  into  muscular  force. 

t  Animals  that  hibernate  show  the  same  truth.  The  marmot,  for  instance,  in 
summer  is  warm-blooded ;  in  the  winter  its  pulse  sinks  from  140  to  4,  and  its 
heat  corresponds.  The  bear  goes  to  his  cave  in  the  fall,  fat ;  in  the  spring  he 
comes  out  lean  and  lank.  Cold-blooded  animals  have  very  inferior  breathing 
apparatus.  A  frog,  for  example,  has  to  swallow  air  by  mouthful!?,  as  we  do 
water.  Others  have  no  lungs  at  all,  and  breathe  in  a  little  air  through  the  skin, 
enough  to  barely  exist.  Is  it  strange  they  are  cold-blooded  1 


86  INORGANIC     CHEMISTRY. 

plex  organic  bodies,  and  the  tension  of  the  pent-up  force 
is  very  great.  Thus  in  flesh,  starch,  sugar,  etc.,  the  mol- 
ecules are  very  large  (see  p.  100),  and,  when  these  oxidize 
into  the  smaller  ones  of  water,  carbonic  acid,  and  am- 
monia, the  hidden  energy  thus  liberated  gives  us  heat 
and  strength.*  It  is  merely  the  transference  of  force 
from  one  organic  body  to  another.  One  decays,  the  other 
grows.  One  drops  in  the  scale  of  life,  the  other  rises. 
One  loses  as  the  other  gains.  As  no  matter  is  either  lost 
or  gained  in  any  chemical  change,  so  also  no  force  is  lost 
or  gained,  but  all  must  be  accounted  for.  Action  and 
reaction  are  equal  in  chemistry  as  in  philosophy. 

2*he  Burning  of  Mie  Body  by  0. — A  man  weigh- 
ing 150  Ibs.  has  64  Ibs.  of  muscle.  This  will  be  burned 
in  about  80  days  of  ordinary  labor.  As  the  heart  works 
day  and  night,  it  burns  out  in  about  a  month.  So  that 
we  have  a  literal  "new  heart"  every  thirty  days.  We 
thus  dissolve,  melt  away  in  time,  and  only  the  shadow  of 
our  bodies  can  be  called  our  own.  They  are  like  the 
flame  of  a  lamp,  which  appears  for  a  long  time  the  same, 
since  it  is  "  ceaselessly  fed  as  it  ceaselessly  melts  away." 
The  rapidity  of  this  change  in  our  bodies  is  remarkable. 
Says  Dr.  Drap'er :  "  Let  a  man  abstain  from  water  and 
food  for  an  hour,  and  the  balance  will  prove  he  has 
become  lighter."  This  action  of  .0,  so  destructive — wast- 
ing us  away  constantly  from  birth  to  death,  is  yet  essen- 
tial to  our  existence.  Why  is  this  ?  Here  is  the  glorious 
paradox  of  life.  We  live  only  as  we  die.  The  moment 
we  cease  dying,  we  cease  living.  All  our  life  is  produced 

*  This  latent  force  is  called  a  potential  one,  and  the  same  force,  when  sensible, 
is  termed  a  dynamic  one.  In  the  former  case  it  is  hidden  and  ready  to  burst 
out  at  any  time ;  in  the  latter,  it  is  in  full  action.  Potential  force  is  contained  in 
the  powder  of  a  loaded  gun.  Dynamic  force  drives  the  bullet  to  the  mark- 


OXYGEN.  SI 

by  the  destruction  of  our  bodies.  No  act  can  be  per- 
formed except  by  the  wearing  away  of  a  muscle.  No 
thought  can  be  evolved  except  at  the  expense  of  the 
brain.  Hence  the  necessity  for  food  to  supply  the  con- 
stant waste  of  the  system,*  and  for  sleep  to  give  nature 
time  to  repair  the  losses  of  the  day.  Thus,  also,  we  see 
why  we  feel  exhausted  at  night  and  refreshed  in  the 
morning. 

0  the  Common  Scavenger.  — God  has  no  idlers  in 
his  world.  Each  atom  has  its  use.  There  is  not  an  extra 
particle  in  the  universe.  The  mission  of  oxygen,  so  de- 
structive in  its  action,  is  therefore  essential,  that  every 
waste  substance  may  be  collected  and  returned  to  the 
common  stock,  for  use  in  nature's  laboratory.  In  per- 
forming this  general  task,  its  uses  are  most  important 
and  necessary.  It  sweetens  water,  it  keeps  the  avenues 
of  the  body  open  and  unclogged,f  it  preserves  the  air 
wholesome.  It  becomes,  in  a  word,  the  universal  scaven- 
ger of  nature.  Every  dark  cellar  of  the  city,  every  recess 
of  the  body,  every  nook  and  cranny  of  creation,  finds  it 
waiting ;  and  the  instant  an  atom  is  exposed,  the  oxygen 
seizes  upon  it.  A  leaf  falls,  and  the  0  forthwith  com- 
mences its  destruction.  A  tiny  twig,  far  out  at  the  end 
of  a  limb,  dies,  and  the  0  immediately  begins  its  removal. 
A  pile  of  decaying  vegetables,  a  heap  of  rubbish,  the  dead 
body  of  an  animal,  a  fallen  tree,  the  houses  we  build  for 

*  This  food  must  be  organic  matter  endowed  with  potential  power  treasured 
Tip  in  the  plant.  When  it  is  transformed  into  flesh,  perhaps  made  still  more 
Vital  in  the  process,  we  have  this  force  standing  ready  to  be  used  again  at  our 
pleasure.  When  we  will  it,  the  O  combines  with  the  flesh  and  sets  free  the  en- 
ergy for  us  to  apply. 

t  Huxley  very  prettily  calls  O,  in  this  connection,  the  "  great  sweeper  "  of  the 
body,  since  it  lays  hold  of  all  the  waste  matter  of  the  system,  and  burning  it  up, 
removes  it  out  of  the  way. 


88  INORGANIC     CHEMISTRY. 

our  shelter,  even  the  monuments  erected  above  our  final 
resting-place,  are  all  gnawed  upon  by  what  we  call  the 
"  insatiate  tooth  of  time."  It  is  only  the  constant  corro- 
sion of  this  destructive  agents-oxygen. 

Action  of  Utidiltited  0  in  the  3?odj>.  —  ThG 
action  of  undiluted  oxygen  on  the  .animal  system  is  exhil- 
arating in  the  highest  degree.  A  rabbit  immersed  in  a 
receiver  of  this  gas  soon  feels  its  effect,  is  thrown  into  a 
delirium  of  excitement,  and  in  a  few  hours  by  this  quick 
combustion  burns  out  its  little  lamp  of  life.  Pure  oxygen 
has  been  administered  in  cases  of  apparent  death  by 
drowning.  Were  it  convenient  to  obtain,  it  would  doubt- 
less be  a  most  excellent  restorative.  Were  we  to  breathe 
undiluted  oxygen,  the  veins  would  presently  dilate  with 
the  increasing  tide  of  blood,  the  eyes  would  glisten  and 
glare,  the  gestures  become  quick  and  startling,  and,  if 
the  inhalation  of  the  gas  still  continued,  fever,  and  at 
last  death,  would  ensue. 

Results  if  the  Mr  were  Undiluted  0.— The 
fire  element  would  run  riot  everywhere.  Metal  lamps 
would  burn  with  the  oil  they  contain.  Our  stoves  would 
blaze  with  a  shower  of  sparks.  A  fire  once  kindled 
would  spread  with  ungovernable  velocity,  and  a  uni- 
versal conflagration  would  quickly  wrap  the  world  in 
flame. 

OZONE. 

Ozone  is  an  allotropic  form  of  0 — *.  e.,  a  form  in  which 
the  element  itself  is  so  changed  as  to  have  new  prop- 
erties. 

Source. — It  is  always  perceived  during  the  working  of 
an  electric  machine,  and  is  then  called  "the  electric 


OZONE. 


39 


smell."  It  has  also  been  detected  near  objects  just  struck 
by  lightning.  Electricity  is  supposed  to  have  something 
to  do  with  the  formation  of  the  ozone  in  the  atmos- 
phere. 

Preparation. —Pour  a  lit- 
tle ether  into  a  jar  of  com- 
mon air,  and  stir  in  its 
vapor  a  heated  glass  rod. 
The  0  will  be  immediately 
changed  into  its  allotropic 
form — ozone — which  can  be 
recognized  by  its  pungent 
odor.  It  may  also  be  tested 
by  a  paper  wet  with  a  mix- 
ture of  starch  and  potassium 

iodide  (KI).     The  OZOne  Sets  Preparing  ozone. 

free  the  iodine,  which  unites 

with  the  starch,  forming  blue  iodide  of  starch.*  At  a 
temperature  a  little  above  that  of  boiling  water,  the  ozone 
will  turn  into  0. 

Properties. — Ozone  is  still  more  corrosive  than  oxy- 
gen. It  bleaches  powerfully,  and  is  a  rapid  disinfect- 
ant. A  piece  of  tainted  meat  plunged  into  a  jar  of  it  is 
instantly  deodorized,  and  it  is  probable  that,  even  in 
minute  quantities,  this  gas  exercises  a  powerful  influence 
in  purifying  the  atmosphere.  Its  over-abundance  in  the 
air  is  supposed  to  produce  influenzas,  diseases  of  the 
lungs,  etc.,  and  its  absence  to  cause  fevers,  agues,  and 
kindred  diseases. 


*  If  a  piece  of  the  dry  iodized  paper  be  exposed  upon  a  clear  day  in  the  open 
air  of  the  country,  in  a  few  minutes  it  will  assume  a  bluish  tint.  In  cloudy, 
foggy  weather,  or  in  cities,  this  effect  is  rarely  observed. 


4Q  INORGANIC     CHEMISTRY. 

A.ntozone  (the  opposite  of  ozone)  is  always  formed 
at  the  same  time  as  ozone,  but  returns  to  ordinary  0 
more  readily.  Its  distinguishing  trait  is  its  tendency  to 
form  clouds  with  0.  We  notice  it  in  the  oxidation  of 
phosphorus,  as  a  white  mist  which  remains  long  after  the 
phosphorus  oxides  have  been  dissolved  by  the  H20.  The 
gray  smoke  that  lingers  around  chimneys,  steam-engines, 
etc.,  is  composed  of  antozone. 

PRACTICAL     QUESTIONS. 

1.  Are  all  acids  sour? 

2.  Wliat  is  the  difference  between  an  ate,  an  ite,  and  an  ide 
compound  ? 

3.  Why  does  not  canned  fruit  decay  ? 

4.  Where  is  the  'higher  oxide  formed,  at  the  forge  or  in  the 
pantry  ? 

5.  Why  is  the  blood  red  in  the  arteries,  and  dark  in  the  veins  ? 

6.  Do  we  need  more  0  in  winter  than  in  summer  ? 

7.  Which  would  starve  sooner,  a  fat  man  or  a  lean  one  ? 

8.  How  do  teamsters  warm  themselves  by  slapping  their  hands 
together  ? 

9.  Could  a  person  commit  suicide  by  holding  his  breath  ? 
10.  Why  do  we  die  when  our  breath  is  stopped  ? 

'11.  Why  do  we  breathe  so  slowly  when  we  sleep  ? 

12.  How  does  a  cold-blooded  animal  differ  from  a  warm-blooded 
one? 

13.  Why  does  not  the  body  burn  out  like  a  candle  ? 

14.  Do  all  parts  of  the  body  change  alike  ? 

15.  What  objects  would  escape  combustion  if  the  air  were  undi- 
luted 0  ? 

16.  How  much  0  can  be  obtained  from  6  oz.  of  KC103  ? 

17.  How  much  KC103  would  be  needed  to  produce  2  Ibs.  of  0  ? 

18.  How  much  KC1  would  be  formed  in  preparing  1  Ib.  of  0  ? 

19.  Name  a  substance  from  which  the  0  can  be  set  free  by  a 
stroke  of  the  hammer. 

20.  Name  one  from  which  the  0  can  only  be  liberated  with 
extreme  difficulty. 


NITROGEN.  41 

21.  Is  it  probable  that  all  the  elements  are  discovered  ? 

22.  Is  heat  produced  by  oxidation  ? 

23.  What  is    the    difference    between   dynamic   and  potential 
force? 

24.  Why  does  running  cause  panting  ? 

25.  How  does  0  give  us  force  ? 

26.  Does  the  plant  produce  force  ? 

27.  If  we  burn  an  organic  body  in  a  stove  it  gives  off  heat ;  in 
the  body  it  produces  also  motion.     Explain. 

28.  In  preparing  N,  a  thin  white  cloud  remains  in  the  jar  for  a 
long  time.     What  is  it  ? 


NITROGEN. 

j  N Atomic  Weight,  14 Specific  Gravity,  0,97, 

THIS  gas  is  called  nitrogen  because  it  exists  in  nitre. 

Sources. — N  forms  £  of  the  atmosphere,  and  is  found 
abundantly  in  ammonia,  nitric  acid,  flesh,*  and  in  such 
vegetables  as  the  mushroom,  cabbage,  horse-radish,  etc. 
It  is  an  essential  constituent  of  the  valuable  medicines, 
quinine  and  morphine,  and  of  the  potent  poisons,  prussic 
acid  and  strychnine. 

Preparation. — As  the  air  consists  FJQ. 

of  N  and  0,  the  easiest  method  of 
obtaining  the  former  gas  is  to  remove 
the  latter.  Place  in  the  centre  of  a 
deep  dish  of  water  a  little  stand  sev- 
eral inches  in  height,  on  which  a 
bit  of  phosphorus  may  be  laid  and  Pw»**ff  »• 

ignited.    As  the  fumes  of  phosphoric  anhydride  ascend, 
invert  a  receiver  over  the  stand.    The  phosphorus  will 

*  Its  compounds  give  to  burnt  hair  and  woolen  their  peculiar  odor. 


J$  INORGANIC     CHEMISTRY. 

consume  the  0  of  the  air  contained  in  the  jar,  leaving 
the  N.  Add  more  H20  as  that  in  the  plate  rises.  It 
should  occupy  i  of  the  receiver.  The  jar  will  at  first  be 
filled  with  white  fumes  (P205),  but  they  will  be -absorbed 
by  the  H20  in  a  short  time. 

Properties. — All  descriptions  of  N  are  of  a  negative 
character.  It  neither  burns  nor  permits  anything  else  to 
burn.  It  neither  supports  life  nor  destroys  it.  Yet  a 
candle  will  not  burn  in  it,  and  a  person  cannot  breathe 
it  alone  and  live,  simply  because  it  shuts  off  the  life- 
giving  0.  So  will  a  person  drown  in  H20,  not  that  the 
water  poisons  him,  but  because  it  fills  his  mouth,  and 
shuts  out  the  air.  N  has  only  a  weak  affinity  for  any  of 
the  elements.  The  instability  of  its  compounds  is  a  strik- 
ing peculiarity.  It  will  unite  with  iodine,  for  example, 
but  a  brush  with  a  feather,  or  a  heavy  step  on  the  floor 
will  set  it  free.* 

Uses. — Delation  of  N  to  Organic  Substances. 
— Four-fifths  of  each  breath  that  enters  our  lungs  is  N  ; 
yet  it  comes  out  as  it  went  in,f  while  that  portion  of  the 
0  which  remains  behind  performs  its  wonderful  work 
within  our  bodies.  One-fifth  of  our  flesh  is  N,  yet  none 
of  it  comes  from  the  air  we  breathe.  Yve  obtain  all  our 
supply  from  the  lean  meat  and  vegetables  we  eat.  Plants 
breathe  the  air  through  the  leaves — their  lungs ;  yet  they 


*  "  Like  a  half-reclaimed  gypsy  from  the  wilds,  it  is  ever  seeking  to  be  free 
again ;  and  not  content  with  its  own  freedom,  is  ever  tempting  others,  not  of 
gypsy  blood,  to  escape  from  thraldom.  Like  a  bird  of  strong  beak  and  broad 
wing,  whose  proper  place  is  the  sky,  it  opens  the  door  of  its  aviary,  and  rouses 
and  flutters  the  other  and  more  peaceful  birds,  till  they  fly  with  it,  although  they 
soon  part  company."— Edinburgh  Beview. 

t  There  is  a  constant  exhalation  of  N  through  the  pores  of  the  skin.  This 
small  amount  is -perhaps  absorbed  in  the  lungs,  but  it  is  of  no  use  to  the  body,  so 
far  asTuiown. 


NITROGEN.  43 

do  not  appropriate  any  of  the  N  obtained  in  this  way, 
but  rely  upon  the  ammonia  and  the  nitric  acid  their 
roots  absorb  from  the  soil.  N  enters  the  stove  with  the  0 
— the  latter  unites  with  the  fuel ;  but  the  former,  having 
no  chemical  attraction,  passes  out  of  the  chimney.  Even 
from  a  blast  furnace,  where  Fe  melts  instantly  like  wax,  N 
comes  forth  without  the  smell  of  fire  upon  it  (p.  150).  So 
inert  is  it,  that  it  will  not  unite  directly  with  any  organic 
substance.  We  must  all,  animals  and  plants,  depend 
upon  finding  it  already  combined  in  some  chemical  com- 
pound, and  so  appropriate  it  to  our  use.  But  even  then 
we  hold  it  very  loosely  indeed.  The  tendency  of  flesh  to 
decompose  is  largely  owing  to  the  instability  of  the  N  in 
its  composition. 

^Difference  between  N  and  0.* — We  see  now 
how  different  N  is  from  0.  The  one  is  the  conservative 
element,  the  other  the  radical.  But  notice  the  nice 
planning  shown  in  the  adaptation  of  the  two  to  our 
wants.  0,  alone,  is  too  active,  and  must  be  restrained  ; 
N,  alone,  is  sluggish,  and  only  fit  to  weaken  a  stronger 
element.  Were  the  air  undiluted  0,  our  life  would  be 
excited  to  a  pitch  of  which  we  can  scarcely  dream,  and 
would  sweep  through  its  feverish,  burning  course  in  a 
few  days ;  were  it  undiluted  N  we  could  not  exist  a 
moment.  Thus  we  see  that,  separately,  either  element  of 
the  air  would  kill  us,  0  by  excess  and  N  by  lack  of  action. 

0  and  N  combined.— -A  mixture  of  fiery  0  and  the 
inert  N  gives  us  the  golden  mean.  The  0  now  quietly 


*  The  difference  between  these  two  gases  can  be  best  illustrated  by  having  a 
jar  of  each,  and  rapidly  passing  a  lighted  candle  from  one  to  the  other;  the  N 
will  extinguish  the  flame,  and  the  O  relight  the  coal.  By  dextrous  management, 
this  may  be  repeated  a  score  of  times. 


44  INORGANIC    CHEMISTRY. 

burns  the  fuel  in  our  stoves  and  keeps  us  warm ;  combines 
with  the  oil  in  our  lamps  and  gives  us  light ;  corrodes  our 
bodies  and  gives  us  strength ;  cleanses  the  air  and  keeps 
it  fresh  and  invigorating ;  sweetens  foul  water  and  makes 
it  wholesome ;  works  all  around  and  within  us  a  constant 
miracle,  yet  with  such  delicacy  and  quietness  that  we 
never  perceive  or  think  of  it  until  we  see  it  with  the  eye 
of  science. . 

Compounds.—  Nitric  Acid,  HN03.*  —  Sources. — 
This  acid  is  found  in  nature,  combined  with  Na  or  K. 
It  is  formed  in  small  quantities  in  the  atmosphere  by  the 

Fig.  9. 


Preparing  HNO8. 

union  of  its  elements  during  the  passage  of  electricity,  as 
in  a  thunder-storm,  and  being  washed  to  the  earth  by 
rain,  is  absorbed  by  the  roots  of  plants. 

Preparation. — It  is  liberated  by  adding  a  stronger  acid 
to  one  of  the  nitrates.  Thus  if  sulphuric  acid  (H2S04) 
and  sodium  nitrate  be  heated  together  in  a;  retort,  the 


*  The  molecule  of  nitric  anhydride  is  N2O5 ;  adding  the  elements  of  water,  we 
have  N2OS  +  H2O  -  2(HNOS),  or  2  molecules  of  nitric  hydride  (nitric  acid).  In 
its  compounds  a  metal  takes  the  place  of  the  H ;  thus,  KNOS,  NaNO3,  etc. 


NITROGEN.  45 

salt  will  be  decomposed  and  the  acid  can  be  collected  in 
a  receiver,  cooled  by  dripping  water. 

Properties. —  It  is  an  intensely  corrosive,  poisonous 
liquid.*  When  pure,  it  is  colorless ;  but  as  sold,  it  has 
commonly  a  golden  tint  from  the  presence  of  a  lower 
oxide  of  N,  produced  by  the  decomposing  action  of  the 
light.  It  has  been  obtained  in  the  form  of  brilliant 
transparent  crystals  (nitric  anhydride),  but  they  decom- 
pose spontaneously.  In  strength  it  is  next  to  H2S04.  It 
was  formerly  called  aqua-fortis,  or  strong  water.  It 
stains  wood,  the  skin,  etc.,  a  bright  yellow.  It  gives 
up  its  0  readily,  and  hence  is  a  powerful  oxidizing 
agentf 

Uses. — HN03  is  employed  in  dyeing  woollen  yellow, 
and  in  surgery  for  cauterizing  the  flesh.  It  dissolves 
most  of  the  metals,  and  in  combination  with  HC1  forms 
aqua-regia,  the  usual  solvent  of  Au.  It  etches  the  lines  in 
copperplate  engraving,  and  the  beautiful  designs  on  the 
blades  of  razors,  swords,  etc.  The  process  is  very  simple. 
The  surface  is  covered  with  a  varnish  impervious  to  the 
acid,  and  the  desired  figure  is  then  sketched  in  the  var- 
nish with  a  needle.  The  H  N03  being  poured  on,  oxidizes 
the  metal  in  the  delicate  lines  thus  laid  bare. 


*  This  fact  shows  the  power  of  chemical  affinity.    The  bland  mixture  we  in- 
hale at  every  breath  is  changed  to  a  corrosive  poison, 
t  The  following  experiments  illustrate  this  property  of  HNOS : 

1.  Mix  equal  parts  of  strong  KNO3  and  H2SO4.    Place  a  little  oil  of  turpen- 
tine in  a  cup  out-of-doors,  and  pour  the  mixture  upon  it  at  arm's  length.    The 
turpentine  will  burn  with  almost  explosive  violence. 

2.  Pour  very  dilute  HNO3  upon  bits  of  tin.    Dense,  red  fumes  (NOa,hyponitric 
anhydride)  will  pass  off,  and  the  Sn  will  be  converted  into  a  white  oxide,  which 
furnishes  what  is  termed  putty  powder. 

3.  Throw  crystals  of  any  nitrate  on  red-hot  coals.     They  will  deflagrate  on 
account  of  the  O  which  they  give  up  to  the  fire. 

4.  Soak  a  strip  of  blotting-paper  in  a  solution  of  nitre.    It  will  form  "  touch- 
paper,"  and  when  lighted  will  only  smoulder. 


INORGANIC     CHEMISTRY. 


Nitrous  Oxide,  .N20. —  Preparation. —  This  gas  is 
made  by  heating  ammonium  nitrate  (H4N,N03),  which 
decomposes  into  H20  and  N20.  (See  p.  135.) 

Fig.  10. 


•  H4N,       NO, 

U" 

2H20 


'*     Preparing  N^O. 

Properties. — N20  is  a  colorless,  transparent  gas  with  a 
faintly  sweetish  taste  and  smell.  It  supports  combustion 
nearly  as  well  as  0,  and  many  of  the  experiments 
ordinarily  performed  with  that  gas  will  be  equally  bril- 
liant with  N20.  If  breathed  for  a  short  time,  it  produces 
a  peculiar  kind  of  intoxication,  often  attended  with  un- 
controllable laughter,  and  hence  it  has  received  the 
popular  name  of  laughing  gas.  The  effect  soon  passes 
off.  If  taken  for  a  longer  time,  it  causes  insensibility, 
and  is  therefore  valuable  as  an  anaesthetic  in  surgical  and 
dental  operations. 

Nitric  Oxide  y  NO.— Preparation. — This  gas  may  be 
prepared  by  the  action  of  dilute  HN03  on  copper  clip- 
pings. The  flask  (a,  Fig.  11)  will  soon  be  filled  with  red 
fumes,  but  a  colorless  gas  will  collect  in  the  jar  over 
water.  At  the  conclusion  of  the  process,  the  flask  will 


NITROGEN. 


contain  a  deep  blue  solution  of  copper  nitrate  (Cu2N03). 
By  filtering  and  evaporating,  the  beautiful  crystals  of 
this  salt  may  be  obtained. 


7,  11, 

8HNO, 


Preparing  NO. 

• 

Properties. — NO  is  a  "colorless,  irrespirable  gas  with  a 
disagreeable  odor.  Its  remarkable  property  is  its  affinity 
for  0.  Let  a  bubble  escape  into  the  air,  and  red  fumes 
of  hyponitric  anhydride  (N02)  will  be  formed.* 

Ammonia,  H3N. — Source. — This  gas  was  formerly 
called  hartshorn,  because  in  England  it  was  made  from 
the  horns  of  the  hart.  It  received  the  name  ammonia, 
by  which  it  is  now  more  generally  known,  from  the  tem- 
ple of  Jupiter  Ammon,  near  which  sal-ammoniac,  one  of 
its  compounds,  was  once  manufactured.  The  aqua- 

*  This  may  be  illustrated  still  more  prettily  by  the  following  experiment : — 
Fill  a  small  jar  with  water  colored  blue  by  litmus  solution,  and  pass  up  into  it 
sufficient  NO  to  occupy  about  one-third  of  the  bottle  ;  the  litmus  will  not  change 
in  color.  Now  allow  a  few  bubbles  of  O  to  rise  into  the  NO  ;  deep  red  fumes 
will  be  formed,  which  will  quickly  dissolve,  and  the  blue  solution  become  red. 
If  both  the  O  and  the  NO  be  pure,  it  is  possible,  by  cautiously  adding  O,  to 
cause  a  complete  absorption  of  both  gases.  If  common  air  were  used  instead  of 
O,  only  N  would  then  remain  in  the  jar. 


48  INORGANIC     CHEMISTRY. 

ammonia  of  the  shops,  which  is  merely  a  strong  solution 
of  the  gas  in  H20,  is  obtained  from  the  incidental  pro- 
ducts of  the  gas-works  in  large  quantities.  (See  p.  83.) 
Its  pungent  odor  can  often  -be  detected  near  decaying 
vegetable  and  animal  matter. 

Preparation. — H3N  is  ordinarily  prepared  by  heating 
gal-ammoniac  with  lime.*     The  stronger  base  unites  with 

Fig.  12. 


HSN  burning  in  O. 

the  Cl,  and  sets  the  ammonia  free.    The  reaction  may 
be  shown  as  follows : 


3(H4N,C1)     +CaO 


2  H3N,  H20  +  CaCl2 

Properties.— Water  at  60°  F.  will  absorb  700  times  its 
own  bulk  of  the  gas.f  This  solution  will  produce  a 
blister,  and  should,  therefore,  be  very  much  weakened 

*  This  may  be  illustrated  by  simply  mixing  in  a  cup  some  powdered  sal- 
ammoniac  and  lime,  when  the  ammonia  may  be  detected  by  its  odor,  and  the 
bluing  of  moist  red  litmus-paper. 

t  Heat  a  little  aqua  ammonia  in  a  Florence  flask.  Dry  the  vapor  and  collect 
in  an  inverted  bottle,  to  which  is  fitted  a  cork  and  tube,  with  the  inner  extremity 
drawn  to  a  fine  point  over  the  spirit-lamp.  Insert  the  cork,  and  then  plunge  the 
bottle  into  a  vessel  of  water.  The  water  which  passes  in  first  will  absorb  the 
gaa  so  quickly  as  to  make  a  partial  vacuum,  into  which  the  water  will  rush  so 
violently  aa  to  produce  a  miniature  fountain. 


NITROGEN.  4$ 

before  being  tasted  or  touched.  It  is  a  strong  alkali,  and 
turns  the  vegetable  blues  to  green;  but  owing  to  its 
volatility  this  change  of  color  is  only  temporary.  It  is, 
therefore,  sometimes  termed  "the  volatile  alkali."  It 
neutralizes  the  most  powerful  acids,  and  forms  important 
salts.  Its  vapor  burns  in  0  with  a  green  flame.  (See 
Fig.  12.)  Its  test  is  HC1. — Example  :  If  we  bring  a  stopple 
wet  with  HC1  near  this  gas,  it  will  instantly  reveal  itself 
by  a  dense  cloud  of  white  fumes,  ammonium  chloride 
(sal-ammoniac),  which  floats  in  the  air  like  smoke.  The 
antidote  of  H3N  is  vinegar.  Gaseous  ammonia  becomes 
liquid  at  a  cold  of  —40°. 

Nascent  State. — If  N  and  H,  the  elements  of  H3N, 
be  mixed  in  a  receiver,  they  will  not  unite  chemically, 
owing  to  the  negative  character  of  N.  When,  however, 
any  substance  is  decomposed  which  contains  both  of 
them,  as  bituminous  coal,  flesh,  etc.,  at  the  very  instant 
of  their  separation  they  will  combine  and  form  H3N, 
When  elements  are  thus  in  the  act  of  leaving  their  com- 
pounds, they  are  said  to  be  in  their  "  nascent  state." 

PRACTICAL     QUESTIONS. 

1.  How  could  you  detect  any  free  0  in  a  jar  of  N  ? 

2.  How  would  you  remove  the  product  of  the  test  ? 

3.  In  the  experiment  shown  in  Fig.  11,  why  is  the  gas  red  in  the 
flask,  but  colorless  wnen  it  bubbles  up  into  the  jar  ? 

4.  How  much  H  3  N  can  be  obtained  from  3  Ibs.  of  sal-ammoniac  ? 

5.  How  much  H  2  0  will  be  formed  in  the  process  ? 

6.  How  much  CaO  will  be  needed  ? 

7.  In  separating  N,  how  much  air  will  be  needed  to  furnish  a 
gallon  of  the  gas  ? 

8.  How  much  N  2  0  can  be  made  from  1  Ib.  of  ammonium  nitrate  ? 

9.  How  much  nitric  acid  can  be  formed  from  50  Ibs.  of  sodium 
nitrate  (NaN03)? 

3 


50  INORGANIC     CHEMISTRY. 

10.  What  causes  flesh  to  decompose  so  much  more  easily  than 
wood? 

11.  If  a  tuft  of  hair  be  heated  in  a  test  tube,  the  liquid  formed 
will  turn  red  litmus-paper  blue.     Explain. 

12.  Why  should  care  be  used  in  opening  a  bottle  of  strong  H  3  N 
in  a  warm  room  ? 

13.  What  weight  of  N  is  there  in  10  Ibs.  of  HN03  ? 

14.  How  much  sal-ammoniac  would  be  required  to  make  2  Ibs. 
of  H3N? 

15.  Give  illustrations  of  the  replacement  of  the  H  in  an  acid  by 
a  metal. 

16.  What  is  the  difference  between  liquid  ammonia  and  liquor 
ammonias  ? 


HYDROGEN. 

Symbol,  H  .  .  .Atomic  Weight,  1  ....  Specific  Gravity,  ,069. 

HYDBOGEN  means  literally  a  generator  of  water. 
Preparation.—  It  is  always  obtained  by  the  decomposi 


.  w. 


Preparing  hydrogen. 


tion  of  H20,  of  which  it  forms  4  part  by  weight.    If  we 
place  in  an  evolution  flask  (a  common  junk  bottle  will 


HYD'ROGEN.  51 

answer)  bits  of  Zn,  and  then  pour  through  the  funnel 
tube  (b)  H20  and  H2S04,  the  gas  will  be  evolved  abun- 
dantly. (See  Appendix.)  The  reaction  is  as  follows : 

H2  SO* +  Zn 
H2      +      ZnS04 

The  Zn  simply  takes  the  place  of  the  H2.  The  black 
specks  floating  in  the  liquid  are  charcoal  from  the  zinc, 
The  milky  look  is  given  by  the  zinc  sulphate  (white 
vitriol)  which  is  formed.  By  evaporating  the  water,  the 
crystals  of  this  salt  may  be  obtained. 

Properties. — H  prepared  in  this  manner  has  a  disagree- 
able odor,  from  various  impurities  in  the  materials  used. 
When  pure,  it  is,  like  0,  colorless,  transparent,  and  odor- 
less. H  has  the  greatest  diffusive  power  of  any  element ; 
.and  in  attempts  made  to  liquefy  the  gas,  it  leaked 
through  the  pores  of  the  thick  iron  cylinders  in  which 
it  was  compressed.  It  is  the  lightest  of  all  bodies,  being 
only  Jj  as  heavy  as  common  air.  It  is  not  poisonous, 
although,  like  N,  it  will  destroy  life  or  combustion  by 
shutting  out  the  life-sustainer,  0.  When  inhaled,  it 
gives  the  voice  a  ludicrously  shrill  tone.  It  can  be 
breathed  for  a  few  moments  with  impunity,  if  it  be  first 
passed  through  lime-water  to  purify  it.  (See  Fig.  13.) 
Owing  to  its  lightness,  it  passes  out  of  the  lungs  again 
directly.  Its  levity  suggested  its  use  for  filling  balloons,* 


*  We  read  in  accounts  of  fetes  at  Paris,  of  balloons  ingeniously  made  to  repre- 
sent various  animals,  so  that  aerial  hunts  are  devised.  The  animals,  however, 
persistently  insist  upon  ascending  with  their  feet  up — a  circumstance  productive 
of  great  mirth  in  the  crowd  of  spectators. 


INORGANIC     CHEMISTRY. 


Fig.  15, 


and  it  has  been  employed  for  that  purpose ;  but  coal 
gas,  which  contains  much  H,  and  is  cheaper,  is  now 
preferred. 

Combustion  of  H. — A  lighted  candle,  plunged  into 
an  inverted  jar  of  H,  is  extinguished,  while 
Fig.  iu.        the  gas  itself  takes  fire,  and  burns  with  a 
feeble  flame.     One  atom  of  the  0  of  the 
air  unites  with  two  atoms  of  the  H,  and 
the  product  of  the  combus- 
tion  is    H20,  which  may  be 
condensed  on   a   cold   tum- 
bler, held  over  a  jet  of  the 
burning  gas.     (See  Fig.  16.) 
Candle  in  H.      The  Philosopher's  Lamp  (see 
Fig.   15)   is  a   more   simple 
means  of  illustrating  the  properties  of  H. 

Mixed  Gases. — A  mixture  of  two 
parts,  by  measure,  of  H,  with  one  part  of  0,  or 
five  parts  of  common  air,  when  ignited,  will 
explode  violently.*  The  heat  generated  by 
the  union  of  H2  and  0,  expands  into  steam 
the  drop  of  H20  thus  formed.  Immediately 
after,  the  steam  being  condensed,  a  vac- 
uum is  produced  and  the  particles  of  air  rushing  in  to 
fill  the  empty  space,  by  their  collision  against  each  other, 
cause  the  deafening  sound.  While  the  detonation  is 
so  great,  the  force  is  slight,  as  may  be  shown  by  explod- 
ing, in  the  hand,  soap-bubbles  blown  with  the  gases.  H 

*  The  H  gun — which  is  simply  a  tin  tube,  closed  at  one  end,  and  provided  with 
\  cork  at  the  other,  having  a  priming-hole  at  the  side— is  used  to  illustrate  this 
fact.  It  may  be  filled  over  the  Philosopher's  Lamp  when  that  is  not  ignited. 
The  gas  is  allowed  to  pass  in  until  the  gun  is  about  a  fifth  full,  as  nearly  as  one 
tan  guess,  when  the  gun  is  removed  and  the  gases  ignited  at  the  priming-hole. 


The.  Philoso- 
pher's Lamp. 


53 


H9O  formed  by  burning  H. 


and  0  may  be  mingled  in  the  right  proportion  for  combus- 
tion, and  though  kept  for  years,  there  will  be  no  change. 


Fig.  17. 


Transferring  gases. 


INORGANIC    CHEMISTRY. 


Fig.  18. 


The  different  atoms  lie  against  one  another  quietly,  with 
no  manifestation  of  their  chemical  affinity,  until  sud- 
denly, at  the  contact  of  the  merest  spark  of  fire,  they 
rush  together  with  a  crash  like  thunder,  and  uniting, 
form  the  bland,  passive  liquid — water. 
Action  of  Spongy  ?P2atinum. — A  piece  of  spongy 
platinum  placed  in  a  jet  of  H  will  ig- 
nite it.  This  curious  effect  seems  to  be 
produced  in  the  following  way:  The 
atoms  of  H  and  the  0  of  the  air  are 
brought  so  closely  together  in  its  minute 
pores  that  they  unite,  and  the  heat  thus 
generated  sets  fire  to  the  gas.  This 
action  is  nicely  shown  by  the  instru- 
ment represented  in  Fig.  18.  It  was 
formerly  used  by  chemists  as  a  conven- 
ient way  of  obtaining  a  light  in  the 
laboratory.  Friction  matches  have  superseded  this  inge- 
nious invention. 

Jfeat  of  ^Burning  H. — A  hydrogen  flame  gives  lit- 
tle light,  but  great  heat.  In  H  and  0,  existing  as  gases, 
there  is  stored  a  vast  amount  of  latent  heat.  (Philosophy, 
p.  232.)  When  they  unite  by  chemical  affinity,  this  force 
is  set  free.  "  In  the  union  of  16  Ibs.  of  0  and  two  of  H, 
sufficient  potential  force  is  developed  to  raise  40,000,000 
Ibs.  a  foot  high." 
Hydrogen  Tones.  \— A  singular  illustration  of  the 

*  Z  is  a  piece  of  zinc  suspended  in  a  mixture  of  H2SO4  and  HaO.  At  the  top 
Is  a  stop-cock,  by  turning  which  the  gas  is  allowed  to  pass  out  from  the  re- 
ceiver /.  It  strikes  upon  a  piece  of  spongy  platinum,  and  ignites  with  a  slight 
explosion. 

t  Another  illustration  of  singing  hydrogen  may  be  represented  in  the  follow- 
ing manner :  Make  a  jar  of  heavy  tin,  in  the  form  of  a  double  cone,  12  inches 
long  and  4  inches  in  diameter.  At  one  apex  fit  a  nozzle  and  cork ;  at  the  other, 


Dobereiner's  Lamp.* 


HYDR  0  G  EN. 


Fig.  19. 


laws  of  sound  can  'be  given  by  simply  holding  a  long 
glass  tube,  by  means  of  a  suitable  clamp,  over  a  minute 
jet  of  burning  H. 
At  first  no  effect 
will  be  produced; 
but  as  we  slowly 
introduce  the  jet 
further  and  fur- 
ther into  the  tube, 
a  faint  sound  is 
heard,  apparently 
in  the  far-off  dis- 
tance. It  gradu- 
ally approaches, 
and  finally  bursts 
into  a  shrill,  con- 
tinuous, musical 
note  —  the  key- 
note of  the  heated 
c  o  1 11  m  n  of  air 
within  the  tube. 
The  flame  is  mo- 
mentarily extin- 
guished and  r  e- 
lighted  with  a  Hydrogen  tones. . 

slight     explosion, 
the  rapid  repetition  of  which  is  supposed  to  produce 

make  several  minute  openings.  Cover  the  holes  with  sealing-wax,  and  draw 
the  cork ;  then  fill  the  jar  with  H,  and  replace  the  cork.  When  ready  for  use, 
hold  the  jar  in  a  vertical  position,  remove  the  wax  from  at  least  one  orifice, 
ignite  the  H  at  that  point,  and  draw  the  cork.  Still  hold  the  jar  quietly,  and  in  a 
minute  or  two  the  tiny  jet  of  H  will  begin  to  sing  like  a  swarm  of  mosquitoes, 
buzzing  and  humming  in  a  most  aggravating  way  until,  unexpectedly,  the  scien- 
tific music  ends  in  a  loud  explosion. 


56  INORGANIC     CHEMISTRY. 

the  musical  note.  Indeed,  the  explosions  may  be  made 
so  slow  that  the  quivering  of  the  flame  can  be  seen, 
and  the  sound  cease  to  be  continuous  as  before.  Let 
us  now  place  the  tube  at  a  point  where  no  clapping 
of  hands  or  unusual  sound  will  start  it  into  song.  Let 
various  tones  be  produced  from  a  violin,  and  we  shall 
find  the  flame  responding  only  to  that  tone  which  is  the 
key-note  of  the  tube,  or  its  octave.  The  violin  player 
will  have  perfect  control  of  this  scientific  music,  and  can 
start,  stop,  or  throw  it  into  violent  convulsions,  even 
across  a  large  hall.  Tubes  of  different  sizes  and  lengths 
will  give  tones  of  diverse  character  and  pitch.*  The 
waves  of  sound  from  the  instrument  augmenting  or  in- 
terfering with  those  in  the  tube  probably  produce  these, 
phenomena.  (See  Philosophy,  p.  183.) 

W  A  T  E  R. 

THE  COMPOSITION  of  H20  is  proved  by  analysis  and 
synthesis — i.  e.,  by  separating  the  compound  into  its 
elements,  and  by  combining  the  elements  to  produce  the 
compound.  We  can  analyze  it  in  the  manner  already 
shown  in  preparing  H,  or  by  passing  through  it  a  gal- 
vanic current,  when  the  0  will  appear  in  bubbles  of  gas 
at  the  positive  pole,  and  the  H  in  a  similar  way  at  the 
negative.  In  the  synthetic  method,  we  mix  the  two 
gases,  and  unite  them  as  we  have  before  by  an  electric 
spark.  The  blacksmith  decomposes  water  when  he  sprin- 
kles it  on  the  hot  coals  in  his  forge.  The  H  burns  with  a 

*  The  singing  of  the  hydrogen  flame  may  be  illustrated  more  simply  by  hold- 
ing the  beaks  of  broken  retorts,  or  large  tubes  of  any  kind,  over  the  flame  of  the 
Philosopher's  Lamp.  Jets  of  different  sizes  may  be  made  by  drawing  out  glass 
tubing  over  the  spirit-lamp. 


WATER. 


pale  flame,  while  the   0   in-  &g.  so. 

creases  the  combustion.   Thus, 

in  a  fire,  if  the  engines  throw 

on  too  little  water,  it  may  be 

decomposed,  and  add  to   the 

fury  of  the  flame.*     To  "  set 

the  North  Kiver  on  fire"  is 

only  a  poetical  exaggeration. 

The  quantity  of  electricity  Analysis  of  water. 

required  to  decompose  a  sin- 
gle grain  of  water  is  estimated  to  be  equal  to  a  power- 
ful flash  of  lightning.  The  enormous  force  necessary  to 
tear  these  two  elements  from  each  other  shows  the  won- 
derful strength  of  chemical  attraction,  f  We  thus  see,  that 
in  a  tiny  drop  of  dew  there  slumbers  the  latent  power  of 
a  thunderbolt. 

Water  m  the  Animal  World.  — The  abundance 
of  water  very  forcibly  attracts  the  attention.  It  composes 
perhaps  f  of  our  flesh  and  blood.  Man  has  been  facetiously 
described  as  12  Ibs.  of  solid  matter  wet  up  in  six  pails  of 
water.  All  plumpness  of  flesh,  and  fairness  of  the  cheek, 
are  given  by  the  juices  of  the  system.  A  few  ounces  of 
water  and  a  little  charcoal  constitute  the  principal  chemi- 
cal difference  between  the  round,  rosy  face  of  sixteen, 


*  "  No  more  heat  is  produced  by  the  action  of  the  HaO,  hut  it  is  in  a  more  avail- 
able form  for  communicating  heat.  The  steam  in  contact  with  incandescent 
charcoal  is  decomposed— the  O  going  to  the  C  to  form  CO2,  and  the  H  being  set 
free.  If  the  C  is  abundant,  and  the  heat  high,  the  CO2  is  also  decomposed,  and 
double  its  volume  of  CO  formed.  The  inflammable  gases,  H  and  CO,  mingled 
with  the  hydrocarbons  always  produced,  are  ignited,  making  the  billows  of  flame 
which  sweep  over  a  burning  building."— S.  P.  SHABPLES. 

t  The  force  needed  to  separate  them  becomes  latent  in  the  gases  as  a  potential 
force,  and  when  they  are  burned  at  any  time  will  be  set  free  as  sensible  heat— 
a  dynamic  force. 


58  INORGANIC    CHEMISTRY. 

and  the  wrinkled,  withered  features  of  three-score  and 
ten.  To  supply  the  constant  demand  of  the  system  for 
water,  each  adult,  in*  active  exercise,  needs  about  three 
pints  per  day,  or  over  half  a  ton  annually.  (See  Phys- 
iology, p.  220.)  When  we  pass  to  lower  orders  of  animals, 
we  find  this  liquid  still  more  abundant.  Sunfishes  are 
little  more  than  organized  water.  Professor  Agassiz 
analyzed  one  found  off  the  coast  of  Massachusetts,  which 
weighed  30  Ibs.,  and  obtained  only  half  an  ounce  of  dried 
flesh.  Indeed,  naturalists  state  that  an  entire  order  of 
animals  (acalephs),  to  which  belong  the  jelly-fish,  me- 
dusa, etc.,  is  composed  of  only  ten  parts  in  a  thousand  of 
solid  matter. 

Water  in  the  Vegetable  World. —  In  the  vege- 
table world  we  find  it  abundant.  Wood  is  composed  of 
6  parts  charcoal  and  5  parts  water,  with  a  little  mineral 
matter  comprising  the  ashes.  Bread  is  half  water ;  and 
of  the  potatoes  and  turnips  cooked  for  our  dinner,  it 
comprises  75  parts  of  one  and  90  of  the  other.  The  fol- 
lowing table  shows  the  proportion  in  common  vegetables, 
fruits,  and  meats : 


Mutton. 
Beef 

71 

.74 

Trout  
Apples.  .  .  . 

.81 
.80 

Cabbage  92 
Cucumbers..  .  .97 

Veal 

.75 

•^x^Jr 

Carrots.  ... 

.83 

Watermelons  .98 

Pork 

.76 

Beets  .  . 

.88 

Water  in  the  Mineral  7T0r^. —Bodies  in  which 
the  water  is  chemically  combined  in  definite  proportions, 
are  often  called  hydrates.  In  the  image  which  the  Italian 
pedler  carries  through  our  streets  for  sale,  there  is  nearly 
1  Ib.  of  H20  to  every  4  PCS.  of  plaster  of  Paris.  One- 
third  of  the  weight  of  any  ordinary  soil  is  this  same 


W A  TE  R.  59 

liquid.  Each,  pound  of  strong  nitric  acid  contains  2f  oz. 
of  water,  which,  if  removed,  would  destroy  the  acid  itself. 
If  we  expel  the  water  from  oil  of  vitriol,  it  will  lose  its 
acid  properties,  and  we  can  handle  it  with  impunity.  In 
bodies  which  are  capable  of  crystallizing,  it  "seems  to 
determine  the  form  and  general  appearance,  and  is  called 
"  the  water  of  crystallization."  If  we  evaporate  this  from 
blue  vitriol,  it  will  lose  its  color  and  become  white  like 
flour.*  A  few  drops  of  H  20  will  restore  the  blue.  If  we 
expel  this  from  alum,  it  will  puif  up,  and  the  transparent 
crystals  will  dry  into  an  incoherent  mass.  Many  salts 
effloresce,  i.  e.,  part  with  their  water  of  crystallization  on 
exposure  to  the  air,  and  crumble  into  a  white  powder. 

Water  as  a  Solvent.  — Water,  having  no  taste,  col- 
or, or  odor  itself,  is  perfectly  adapted  to  be  the  universal 
solvent.  It  becomes  at  pleasure  sweet,  sour,  salt,  bitter, 
nauseous,  and  even  poisonous.  Had  water  any  taste,  the 
whole  science  of  cookery  would  be  changed,  since  each 
substance  would  partake  of  the  one  universal  watery 
flavor. 

'Pure  Water. — Kain-water,  caught  after  the  air  is 
thoroughly  cleansed  by  previous  showers,  and  at  a  dis- 
tance from  the  smoke  of  cities,  is  the  purest  natural 
water  known.  It  is  tasteless,  yet  its  insipidity  makes  it 
seem  to  us  very  ill-flavored  indeed.  "We  have  become  so 
accustomed  to  the  taste  of  the  impurities  in  hard  wa^r, 
that  they  have  become  to  us  tests  of  its  sweetness  and 
pleasantness. 

Water ?  though  it  may  have  less  mineral  mat- 


*  This  may  be  easily  shown  by  filling  the  bowl  of  a  tobacco-pipe  with  crystals 
of  the  salt,  and  heating  them  over  a  lamp  or  in  the  fire  until  the  water  of  crys- 
tallization is  expelled.  Alum  may  be  made  anhydrous  in  the  same  way. 


60  INORGANIC     CHEMISTRY. 

ter  than  spring  water,  is  often  unfitted  for  drinking  on 
account  of  the  organic  matter  it  contains.  Happily,  run- 
ning water  has  in  itself  a  certain  purifying  power,  owing 
to  the  air  which  it  holds  in  solution ;  so  that,  paradoxical 
as  it  may  seem,  organic  substances  are  burned  in  it  as  cer- 
tainly as  they  would  be  in  a  stove.  Still,  in  order  to  avoid 
any  danger,  river  water  should  be  filtered  through  char- 
coal or  sand  before  using.* 

JETard  Water.  —  As  water  percolates  through  the 
soil  into  our  wells,  it  dissolves  the  various  mineral  mat- 
ters characteristic  of  the  locality.  The  most  abundant 
of  these  are  lime,t  salt,  and  magnesia.  The  former  pro- 
duces a  fur  or  coating  on  the  bottom  of  our  tea-kettles, 
if  we  live  in  a  limestone  region.  When  we  put  soap  in 
such  water,  it  curdles — i.  e.,  it  unites  with  the  lime  (CaO), 
forming  a  new,  or  lime  soap,  which  is  insoluble  in  H20. 
H20  containing  an  excess  of  mineral  matter  is  unwhole- 
some ;  yet  it  is  probable  that  the  sparkling  hard  waters 
of  the  limestone  districts  are  relished,  not  only  because 
they  are  pleasant  to  the  eye  and  agreeable  to  the  taste, 
but  on  account  of  some  hygienic  properties  in  the  excess 
of  CO  2  they  contain,  and  possibly  because  the  CaO  acts 
medicinally  on  the  system.  J 

*  A  weak  solution  of  potassium  permanganate  is  an  excellent  test  of  the 
presence  of  organic  matter.  Place  the  water  to  be  examined  in  a  glass,  and  add 
a  little  permanganate  ;  if  organic  matter  is  present  the  violet  permanganate  solu- 
tion is  decolorized  as  fast  as  added  until  all  the  organic  matter  is  oxidized. 

t  It  is  a  fact  worthy  of  note  that  lime  and  oxide  of  iron,  which  are  frequently 
found  in  HaO,  the  latter  generally  in  minute  quantities,  are  both  healthful ;  while 
the  oxides  of  the  other  metals  are  poisonous.  Were  zinc  or  barium,  for  instance. 
as  common  near  our  homes  as  iron  or  calcium,  wholesome  drinking  water  would 
be  rarely,  if  ever,  found.  By  a  wise  arrangement  of  an  ever-watchful  Provi- 
dence, those  dangerous  metals  are  rare,  and  hidden  far  from  the  haunts  of  man. 

J  The  French  authorities  are  so  well  satisfied  of  the  superiority  of  bard  water, 
that  they  pass  by  that  of  the  sandy  plains,  near  Paris,  and  go  far  away  to  the 
chalk  hills  of  Champagne,  where  they  find  water  even  harder  than  that  of  Lon- 


WATER.  61 

Sea  -  Water.  — The  most  abundant  mineral  in  the 
ocean  is  common  salt.  Yet  it  contains  traces  of  every 
substance  soluble  in  water,  which  has  been  washed  into 
the  sea  from  the  surface  of  the  continents  during  all  the 
ages  of  the  past.  Its  saline  constituents  are  now  in  the 
proportion  of  about  \  oz.  to  1  ]b.  This  amount  may 
be  slowly  increasing,  as  the  water  which  evaporates  from 
the  surface  is  comparatively  pure,  containing  only  a  mere 
trace  of  a  few  substances,  which  give  to  the  sea-breeze  its 
peculiar  bracing,  tonic  influence.  In  this  way,  the  water 
of  the  Salt  Lake  has  become  a  strong  brine,  nearly 
\  of  its  whole  weight  consisting  of  saline  matter.  This 
condition  would  soon  disappear  if  an  outlet  could  be 
provided. 

Water  Atmosphere. — As  the  world  of  waters  is 
inhabited,  it  also  has  its  atmosphere.*  Inasmuch  as  the 
H20  dilutes  the  0  in  part,  it  does  not  need  so  much  N 
as  the  common  air.  It  is  accordingly  composed  of  over 
}  0  instead  of  only  J.  The  air  so  rich  in  0  thus  absorbed 
by  the  water  gives  to  it  life  and  briskness.  If  it  be  ex- 
pelled by  boiling,  the  water  tastes  flat  and  insipid. 

"Paradoxes  of  Water. — "Cold  contracts,"  is  the 
law  of  physics;  but  as  H20  cools,  it  obeys  this  principle 
only  as  far  as  39°  F.  Then  it  slowly  expands,  cooling 
down  to  32°,  its  freezing  point,  when  its  crystals  sud- 
denly dart  out  at  angles  to  each  other,  and  thus,  increas- 


don ;  giving  as  a  reason  for  the  preference  that  more  of  the  conscripts  from  the 
soft-water  districts  are  rejected  on  account  of  the  want  of  strength  of  mus- 
cle, than  from  the  hard-water  districts ;  from  which  they  conclude  that  the  cal- 
careous matter  is  favorable  to  the  formation  of  the  tissues. 

*  Fish  inhale  O  through  the  fine  silky  filaments  of  their  gills.  When  a  fish 
is  drawn  out  of  H2O,  these  dry  up.  and  it  is  unable  to  breathe,  although  it  is 
in  a  more  plentiful  atmosphere  than  it  is  accustomed  to  enjoy. 


62  INORGANIC     CHEMISTRY. 

ing  in  size  about  ^  it  congeals  to  ice.  By  this  wise  ar- 
rangement, ice  is  lighter  than  water,  and  so  swims  on  top ; 
otherwise  our  rivers  would  freeze  solid,  killing  the  fish 
and  aquatic  plants.  The  longest  summer  could  not  melt 
such  an  immense  mass  of  ice.  But  now  the  blanket  that 
Nature  kindly  weaves  over  the  rivers  and  ponds  keeps 
their  finny  inhabitants  warm  and  comfortable  till  spring ; 
then  she  floats  it  south  to  melt  under  a  hotter  sun.  We 
give  to  water  such  contradictory  terms  as  "  hard "  and 
"  soft,"  "  fresh  »  and  "  salt."  H20  seems  the  most  yield- 
ing of  substances,  yet  the  swimmer  who  falls  on  his  face, 
instead  of  striking  head  foremost,  appreciates  the  mis- 
take, and  we  could  drive  a  nail  into  a  solid  cube  of  steel 
as  easily  as  into  a  hollow  one  perfectly  filled  with  H20. 
H  is  the  lightest  substance  known,  and  0  is  an  invisible 
gas ;  yet  they  unite  and  form  a  liquid  whose  weight  we 
have  often  experienced,  and  a  solid  which  makes  a  pave- 
ment hard  like  granite.  H  burns  readily,  and,  when 
mixed  with  0,  explodes  most  fearfully ;  0  supports  com- 
bustion brilliantly — yet  the  two  combined  are  used  to 
extinguish  fires.  H  or  0  in  excess  would  destroy  life ; 
H20  is  so  essential  to  it  that  thirst  causes  a  lingering, 
painful  death. 

U~ses  of  Water. — The  uses  of  H20  are  as  diverse 
as  they  are  practical.  Its  properties  fit  it  for  a  wonderful 
variety  of  operations  in  nature.  Its  office  is  not  merely 
to  moisten  our  lips  on  a  hot  day,  to  make  a  cup  of  coffee, 
to  lay  the  dust  in  the  street,  and  to  sprinkle  our  gar- 
dens ;  it  has  grander  and  more  profound  uses  than  any 
of  these.  Water  is  the  common  carrier  of  creation.  It 
dissolves  the  elements  of  the  soil,  and,  climbing  as  sap 
up  through  the  delicate  capillary  tubes  of  the  plant, 


WATER.  63 

furnishes  the  leaf  with  the  materials  of  its  growth.  It 
flows  through  the  body  a"s  blood,  floating  to  every  part 
of  the  system  the  life-sustaining  0,  and  the  food  neces- 
sary for  repairs  and  for  building  up  the  various  parts  of 
the  "  house  we  live  in."  It  comes  in  the  clouds  as  rain, 
bringing  to  us  the  heat  of  the  tropics,  and  tempering  our 
northern  climate,  while  in  spring  it  floats  the  ice  of  our 
rivers  and  lakes  away  to  warmer  seas  to  be  melted.  It 
washes  down  the  mountain  side,  levelling  its  lofty  sum- 
mit and  bearing  mineral  matter  to  fertilize  the  valley 
beneath.  It  propels  water-wheels  working  forges  and 
mills,  and  thus  becomes  the  grand  motive-power  of  the 
arts  and  manufactures.  It  flows  to  the  sea,  bearing  on 
its  bosom  ships  conducting  the  commerce  of  the  world. 
It  passes  through  the  arid  sands,  and  the  desert  forth- 
with buds  and  blossoms  as  the  rose.  It  limits  the  bounds 
of  fertility,  decides  the  founding  of  cities,  and  directs  the 
flow  of  trade  and  wealth. 

PRACTICAL     QUESTIONS. 

1.  Why,  in  filling  the  hydrogen  gun,  do  we  use  5  parts  of  com- 
mon air  to  2  of  H,  and  only  1  part  of  0  to  2  of  H  ? 

2.  Why  are   coal  cinders    often    moistened  with    H2O   before 
using  ? 

3.  What  injury  may  be  done  by  throwing  a  small  quantity  of 
H20  on  a  fire? 

4.  Why  does  the  hardness  of  water  vary  in  different  localities  ? 

5.  What  causes  the  variety  of  minerals  in  the  ocean?    Is  the 
quantity  increasing  ? 

6.  Is  there  not  a  compensation  in  the  sea-plants,  fish,  etc.,  which 
are  washed  back  on  the  land  ? 

7.  Since  "  all  the  rivers  flow  to  the  sea,"  why  is  it  not  full  ? 

8.  What  is  the  cause  of  the  tonic  influence  of  the  sea  breeze  ? 

9.  When  fish  are  taken  out  of  the  water,  and  thus  brought  into 
a  more  abundant  atmosphere,  why  do  they  die  ? 


64  INORGANIC     CHEMISTRY. 

10.  Do  all  fish  die  when  "brought  on  land  ? 

11.  What  weight  of  water  is  there  in  a  cwt.  of  sodium  sulphate 
(Na2S04,  10H20),  or  Glauber's  salt? 

12.  What  weight  of  water  in  a  ton  of  alum  (KAI2S04>  12H20)  ? 

13.  How  much  water  would  it  require  to  change  5  Ibs.  of  nitric 
anhydride  to  nitric  acid  ? 

14.  How  does  the  air  purify  running  water  ? 

15.  What  is  the  action  of  potassium  permanganate  as  a  disin- 
fectant ? 

16.  Why  does  lime   sometimes  soften  hard  water  when  added 
to  it? 

17.  What  weight  of  H  can  be  obtained  from  a  gallon  of  water  ? 

18.  In  decomposing  H20,  65  parts  by  weight  of  Zn  yield  2  parts 
by  weight  of  H.    How  much  Zn  must  be  employed  to  obtain  100 
Ibs.  of  H  ? 

19.  How  much  KC103  would  be  required  to  evolve  sufficient  0  to 
burn  the  H  produced  by  the  decomposition  of  2  Ibs.  of  H.20  ? 

20.  How  much  0  would  be  required  to  oxidize  the  metallic  Cu 
which  could  be  reduced  from  its  oxide  by  passing  over  it,  when 
white-hot,  20  gr.  of  H  gas  ? 

21.  How  much  0  would  be  required  to  oxidize  the  metallic  Fe 
which  could  be  reduced  in  the  same  manner  by  10  grs.  of  H  gas? 

22.  Why  are  rose-balloons  so  buoyant  ? 

23.  How  much  H  must  be  burned  to  produce  a  ton  of  water  ? 


C   A  R  B   O   N;  > 

Symbol,  C.  Atomic  Weight,  12,  Specific  Gravity  of  Diamond,  3.3  to  3.5, 

Source. — C  is  one  of  the  most  abundant  substances  in 
nature,  forming  nearly  one-half  of  the  entire  vegetable 
kingdom,  and  being  a  prominent  constituent  of  lime- 
stone, corals,  marble,  magnesian  rocks,  etc.  "We  find  it 
in  three  distinct  forms  or  allotropic  conditions — viz.,  the 
diamond,  graphite,  and  amorphous  carbon.  This  last 
term  means  without  crystalline  form,  and  includes  gas- 


CARBON.  65 

carbon,  charcoal,  lamp-black,  coal,  coke,  peat,  soot,  bone- 
black  and  ivory-black.  In  each  of  these  various  sub- 
stances C  possesses  different  properties ; .  yet  any  impuri- 
ties it  may  contain  seem  entirely  incidental,  and  not  at 
all  necessary  to  its  new  state. 

(Proof  of  this  Attotrojpic  state. — Chemists  have 
changed  most  of  these  substances  into  other  allotropic 
forms.  Thus,  common  charcoal  has  been  turned  into 
graphite,  mineral  coal  into  gas-carbon,  the  diamond  into 
coke.  All  of  them,  when  heated  in  the  open  air,  unite 
with  the  same  quantity  of  0,  forming  precisely  the  same 
compound — carbonic  anhydride — from  which  the  C  can 
be  obtained  again  in  the  form  of  charcoal. 

Fhe  jDiamond  is  pure  carbon  crystallized.  It  is 
the  hardest  of  all  known  substances,  scratches  all  other 
minerals  and  gems,  and  can  bs  cut  only  by  its  own  dust. 
It  is  infusible,  but  will  burn  at  a  high  temperature. 
It  is  found  in  various  parts  of  the  world  — North  Carolina, 
Georgia,  Borneo,  Brazil,  and  South  Africa.  In  1858, 
Brazil  furnished  120,000  carats.*  They  usually  appear 
as  semi-transparent,  rounded  pebbles,  enclosed  in  a  thin, 
brownish,  opaque  crust,  which  being  broken  reveals 
the  brilliant  gem  within.  They  are  of  various  tints, 
though  often  colorless  and  perfectly  transparent.  The 
last  are  most  highly  esteemed,  and,  from  their  resem- 
blance to  a  drop  of  clear  spring- water,  are  called  diamonds 
of  the  "  first  water."  They  are  exceedingly  brittle,  and 
valuable  gems  are  said  to  have  been  broken  by  simply 


*  A  carat  is  equal  to  4  grs.  Troy.  The  term  is  derived  from  the  name  of  a  bean 
which,  when  dried,  was  formerly  used  in  weighing  by  the  diamond  merchants 
in  India. 


66  INORGANIC     CHEMISTRY. 

falling  to  the  floor.    Nothing  definite  is  known  concern- 
ing the  origin  of  this  gem.* 

2~?ie  ^Diamond  is  Ground  by  means  of  its  own 
powder.  Being  fitted  to  the  end  of  a  stick  or  handle,  it 
is  pressed  down  firmly  against  the  face  of  a  rapidly  re- 
volving wheel,  covered  with  dia- 
mond-dus-t  and  oil.  This,  by  its 
friction,  removes  the  exposed  edge 
and  forms  a  facet  of  the  gem. 
There  are  three  forms  of  cutting — 

The  brilliant.      The  rose.  6 

the  brilliant,  the  rose,  and  the  table. 
The  brilliant  has  a  flat  surface  on  the  top,  with  facets  at 
the  side,  and  also  below,  the  latter  terminating  in  a 
point,  so  arranged  as  to  refract  the  light  most  brilliantly. 
This  form  shows  the  gem  to  the  best  advantage,  but  is 
used  only  in  large,  thick  stones,  as  it  sacrifices  nearly 
half  the  weight  in  cutting.  The  rose  is  flat  beneath, 
while  the  upper  surface  is  ground  into  triangular  facets, 
terminating  at  a  common  vertex.  The  table  form  is  em- 
ployed for  thin  specimens,  which  are  merely  ornamented 
by  small  facets  on  the  edge.  The  diamond  is  valued  not 


*  Although  the  diamond  is  simply  pure  carbon,  yet  it  has  never  been  made  by 
any  chemical  process.  Minute  diamonds,  it  is  said,  have  been  separated  from 
carbon  compounds  by  long-continued  voltaic  action,  but  they  were  invisible  ex- 
cept with  a  microscope.  The  value  of  the  diamond  varies  with  the  market ;  the 
general  rule  is  as  follows  :  a  gem  ready  for  setting,  of  one  carat  weight,  is  worth 
$150  to  $180 ;  beyond  this  size,  the  estimated  value  increases  according  to  the 
square  of  the  weight,  but  in  case  of  large  stones  is  generally  much  less  than  that 
amount,  although  rare  beauty  or  size  may  greatly  enhance  the  price.  The  Kohi- 
noor  (mountain. of  light,  now  among  the  crown  jewels  of  England)  weighs  103 
carats,  yet  is  valued  at  $10,000,000.  Owing  to  the  discovery  of  many  large  dia- 
monds in  South  Africa,  the  value  of  such  stones  has  much  decreased  of  late. 
The  smaller  ones,  however,  are  becoming  more  expensive  on  account  of  the 
greater  demand  for  them.  The  South  African  diamonds  are  seldom  colorless, 
having  generally  a  yellowish  tint.  Paste  diamonds  are  now  made  in  Paris, 
which  are  so  perfect  an  imitation  that  only  experts  can  distinguish  them  from 
the  real  gems. 


CARBON.  67 

alone  for  its  rarity  and  high  refractive  power,  by  which 
it  flashes  such  vivid  and  brilliant  colors,  but  also  for  its 
mechanical  uses.  For  cutting  glass,  the  curved  edges  of 
the  natural  crystal  are  used. 

Graphite  or  *P2umbago  is  also  called  black-lead, 
because  on  paper  it  makes  a  shining  mark  like  lead.  It 
is  found  at  Ticonderoga,  K  Y.,  Brandon,  Vi,  and  Stur- 
bridge,  Mass.  It  is  supposed  to  be  of  vegetable  origin. 

Uses. — -It  is  chiefly  useful  in  pencils.  For  this  pur- 
pose a  mixture  of  black-lead,  antimony,  and  sulphur — 
the  proportion  of  these  ingredients  determining  the 
hardness  of  the  pencil — is  melted  and  cast  into  blocks, 
which  are  then  sawed  into  thin  slips,  as  seen  in  com- 
mon pencils.*  Though  graphite  seems  very  soft,  yet  its 
particles  are  extremely  hard,  and  the  saws  used  in  cut- 
ting it  soon  wear  out.  We  notice  this  property  in  sharp- 
ening a  pencil  with  a  knife.  Graphite  mixed  with  clay 
is  made  into  black-lead  crucibles.  These  are  the  most 
refractory  known,  and  are  used  for  melting  gold  and 
silver.  It  is  also  sold  as  "  British  lustre,"  "  carburet  of 
iron,"  "  stove  polish,"  etc.,  which  are  employed  for  black- 
ing stoves  and  protecting  iron  from  rusting. 

Gas- Carbon  is  formed  on  the  interior  of  the  re- 
torts used  in  coal-gas  works.  It  has  a  metallic  lustre, 
and  will  scratch  glass. 

Char co a2  is  made  by  burning  piles  of  wood,  so 
covered  over  with  turf  as  to  prevent  free  access  of  air. 
The  volatile  gases,  water,  etc.,  are  driven  off,  and  the  C 

*  For  drawing-pencils,  pure  graphite  powder  is  subjected  to  such  enormous 
pressure  that  the  particles  are  brought  near  enough  together  for  the  attraction 
of  cohesion  to  hold  them  in  a  solid  form,  when  the  pressure  is  removed.  This 
block  is  then  sawed  into  prisms,  which  are  fitted  into  cylinders  of  cedar- 
wood. 


68 


INORGANIC     CHEMISTRY. 


left  behind.    This  forms  about  |  of  the  bulk  of  the  wood 
and  \  its  weight.    Charcoal  for  gunpowder  and  for  medi- 


Making  charcoal. 

cinal  purposes  is  prepared  by  heating  willow  or  poplar 
wood  in  iron  retorts. 

Properties. — It  is  the  most  unchangeable  of  all  the  ele- 
ments, so  that  even  in  the  charcoal  we  can  trace  all  the 
delicate  structure  of  the  plant  from  which  it  was  made. 
It  is  insoluble  in  any  ordinary  liquid.  None  of  the  acids, 
except  nitric,  corrodes  it.  No  alkali  will  eat  it.  Neither 
air  nor  moisture  affects  it.  Wheat  has  been  found  in  the 
ruins  of  Herculaneum  that  was  charred  1800  years  ago, 
and  yet  the  kernels  are  as  perfect  as  if  grown  last  harvest 
The  ground  ends  of  posts  are  rendered  durable  by  char- 


CARBON.  69 

ring.  Indeed,  some  were  dug  up  not  long  since  in  the 
bed  of  the  Thames  which  were  placed  there  by  the  an- 
cient Britons  to  oppose  the  passage  of  Julius  Caesar  and 
his  army.  A  cubic  inch  of  fine  charcoal  has,  it  is  said, 
100  feet  of  surface,  so  full  is  it  of  minute  pores.  These 
absorb  gases  by  capillary  attraction  to  an  almost  incredi- 
ble extent.  A  bit  of  C  will  take  up  90  times  its  bulk  of 
ammonia.  As  the  various  gases  and  the  0  of  the  air  are 
brought  so  closely  together  within  its  pores,  rapid  oxida- 
tion is  produced,  as  in  the  case  of  spongy  platinum  (see 
p.  54).  Pans  of  charcoal  soon  purify,  and  sweeten  the 
offensive  air  of  a  hospital.  Foul  water  filtered  through  C 
loses  its  impurities.  Beer  by  this  process  parts  not  only 
with  its  color  but  with  its  bitter  taste.  Ink  is  robbed 
of  its  value  and  comes  out  clear  and  transparent  as 
water. 

deoxidizing  or  deducing  Action  of  C.  —  At 
a  high  temperature  the  attraction  of  C  for  0  is  powerful. 
In  the  heat  of  a  furnace  it  will  take  it  from  almost  the 
stablest  compounds.  This  fact  gives  to  charcoal  great 
value  in  the  arts.  Nearly  all  the  metals  and  many  of  the 
other  elements  are  locked  up  in  the  rocks  with  0,  and 
C  is  the  key  made  by  the  Creator  for  unlocking  the 
treasure-houses  of  nature  for  the  supply  of  our  wants. 
By  noticing  the  process  of  preparing  zinc,  iron,  phospho- 
rus, etc.,  we  shall  see  the  importance  of  this  property  of 
C.  A  very  pretty  illustration  is  shown 
by  placing  a  few  grains  of  litharge 
(PbO)  on  a  flat  piece  of  charcoal,  and 
directing  upon  it  the  flame  of  a  blow- 
pipe. The  metal  will  immediately  ap- 

J     *          PbO  on  charcoal. 

pear  in  little  sparkling  globules. 


70  INORGANIC    CHEMISTRY. 

Soot  is  unburnt  carbon  which  passes  off  from  a  lamp 
or  fire  when  there  is  not  enough  0  present  to  combine 
with  all  the  C  of  the  fuel.  This,  therefore,  comes  away 
in  flakes,  and  blackens  the  chimney  of  the  lamp,  or  lodges 
in  the  chimney  of  the  house.  After  a  time,  a  large 
quantity  having  collected,  we  are  startled  by  the  cry, 
"  The  chimney  is  on  fire ! "  while  with  a  great  roar  and 
flame  the  soot  burns  out.  This  unpleasant  occurrence  is 
much  more  frequent  when  green  wood  is  used  for  fuel. 
The  H20  of  the  wood  absorbs  much  of  the  heat  of  the 
fire,  and  so  permits  the  C  to  pass  off  unconsumed. 

ZtCtmpblacfc  is  obtained  by  imperfectly  burning  pitch 
or  tar.  The  dense  cloud  of  smoke  is  conducted  into  a 
chamber  lined  with  sacking,  upon  which  the  soot  collects. 
It  is  largely  used  in  painting.  It  is  mixed  with  clay  to 
form  black  drawing-crayons,  and  with  linseed  oil  to  make 
printers'  ink.  Lampblack  has  peculiar  properties  which 
fit  it  for  printing.  Nothing  in  nature  could  supply  its 
place.  No  matter  how  finely  it  is  pulverized,  it  retains 
its  dead-black  color.  The  minutest  particle  is  as  black 
as  the  largest  mass.  It  is  insoluble  in  all  liquids.  It 
never  decays.  The  paper  may  moulder ;  we  may  even 
burn  it ;  and  still,  in  the  ashes,  we  can  trace  the  form  of 
the  printed  letter.  The  ancients  used  an  ink  composed 
of  gum-water  and  lampblack,  and  manuscripts  have  been 
exhumed  from  the  ruins  of  Pompeii  and  Herculaneum 
which  are  yet  perfectly  legible. 

&nima2  C?iarcoa2,  or  bone-black,  is  made  by  burn- 
ing bones  in  close  vessels.  Mixed  with  H2S04  it  forms 
the  basis  of  paste-blacking.  It  is  largely  used  by  sugar 
refiners  (p.  190).  Common  vinegar  filtered  through  it 
becomes  the  white  vinegar  of  the  pickle  manufacturers. 


CARBON.  71 

Mineral  Coal. — This  was  formed  at  an  early  period 
of  the  world's  history,  called  the  Carboniferous  Age. 
The  earth  was  then  pervaded  by  a  genial,  tropical  climate. 
The  air  was  denser  and  richer  with  vegetable  food  than 
now.  The  earth  itself  was  a  swamp,  moist  and  hot,  in 
which  simple  ferns  towered  into  trunks  a  foot  and  a  half 
in  diameter ;  and  where  plants  like  those  which  creep  at  our 
feet  to-day,  or  are  known  only  as  rushes  or  grasses,  grew 
to  the  height  of  lofty  trees.  The  song  of  bird  or  hum  of 
insect  rarely  echoed  through  the  mighty  fern-forests; 
but  a  strange  and  grotesque  vegetation  flourished  with 
more  than  tropical  luxuriance.  In  these  swamps  accu- 
mulated a  vast  deposit  of  leaves  and  fallen  trunks  which, 
under  the  water,  gradually  changed  to  charcoal.  In  the 
process  of  time,  the  earth  settled  at  various  points,  and 
floods  poured  in,  bringing  sand,  pebbles,  clay,  and  mud, 
filling  up  all  the  spaces  between  the  trees  that  were  stand- 
ing, and  even  the  hollow  trunks  themselves.  The  pres- 
sure of  this  soil  and  the  internal  heat  of  the  earth  com- 
bined to  expel  the  gases  from  the  vegetable  deposits,  and 
convert  them  into  mineral  coal.*  In  time  this  section 
was  elevated  again,  and  another  forest  flourished,  to  be  in 
its  turn  converted  into  coal.  Each  of  these  alternate  ele- 
vations and  depressions  produced  a  layer  of  coal  or  of 
soil.  In  these  beds  of  coal  we  now  find  the  trunks  of 
trees,  the  outlines  of  trailing  vines,  the  stems  and  leaves 
of  plants  as  perfectly  preserved  as  in  a  herbarium,  so  that, 
to  the  botanist,  the  flora  of  the  Carboniferous  age  is 
nearly  as  complete  as  that  of  our  own. 

*  Where  this  process  was  nearly  complete,  anthracite  coal,  and  where  only 
partially  finished,  bituminous  coal,  was  formed.  The  greater  the  pressure,  the 
harder  and  purer  the  carbon  produced ;  unless,  however,  the  covering  was  not 
sufficiently  porous  to  allow  the  gases  to  escape,  when  bituminous  coal  was  the 
result. 


72  INORGANIC     CHEMISTRY. 

Co  foe  is  the  refuse  of  gas-works,  obtained  by  distilling 
the  water,  tar,  and  volatile  gases  from  bituminous  coal. 
It  is  burned  in  locomotives,  blast-furnaces,  etc. 

(Peat  is  an  accumulation  of  half  decomposed  vegetable 
matter  in  swampy  places.*  It  is  produced  mainly  by  a 
kind  of  moss  which  gradually  dies  below  as  it  grows 
above,  and  thus  forms  beds  of  great  thickness.  Some- 
times, however,  plants  may  grow  in  the  form  of  a  turf, 
and  decay,  thus  collecting  a  vast  amount  of  vegetable 
debris.  This  gradually  undergoes  a  change,  and  becomes 
a  brownish  black  substance,  loose  and  friable  in  its  text- 
ure, resembling  coal,  but,  unlike  it,  containing  20  to  30 
per  cent,  of  0.  Peat  is  used  in  large  quantities  as  a  fuel. 
For  this  purpose  it  is  cut  out  in  square  blocks  and  dried 
in  the  sun.  In  some  beds  it  is  first  finely  pulverized, 
then  pressed  into  a  very  compact  form  like  brick. 

Mucfc  is  an  impure  kind  of  peat,  not  so  fully  carbon- 
ized ;  though  the  term  is  frequently  applied  to  any  black 
swampy  soil  which  contains  a  large  quantity  of  decaying 
vegetable  matter.  Like  charcoal,  it  absorbs  moisture  and 
gases,  and  is  therefore  used  as  a  fertilizer. 

Various  Forms  and  Uses  of  Carbon .  —  We 
have  seen  in  what  contrary  forms  C  presents  itself.  It  is 
soft  enough  for  the  pencil-sketch,  and  hard  enough  for 
the  glazier's  use.  Black  and  opaque,  it  expresses  thought 
on  the  printed  page :  clear  and  brilliant,  it  gleams  and 
flashes  in  the  diadem  of  a  king.  In  lampblack,  it  fre- 
quently takes  fire  spontaneously ;  in  graphite,  it  resists 
the  heat  of  the  fiercest  flame ;  in  the  diamond,  it  is  an 


*  These  peat-beds  are  of  vast  extent.  One-tenth  of  Ireland  is  covered  by 
them.  A  bed  near  the  mouth  of  the  River  Loire,  is  said  to  be  fifty  leagues  in 
circumference. 


CARBON.  73 

insulator ;  while  in  charcoal,  it  is  so  perfect  a  conductor 
of  electricity  that  it  is  packed  about  the  foot  of  lightning- 
rods  to  complete  the  connection  with  the  earth.  "We 
burn  it  in  our  lamps,  and  it  gives  us  light ;  we  burn  it  in 
our  stoves,  and  it  gives  us  heat ;  we  burn  it  in  our  en- 
gines, and  it  gives  us  power;  we  burn  it  in  our  bodies, 
and  it  gives  us  strength.  As  fuel,  it  readily  unites  with 
0,  yet  we  spread  it  as  stove-polish  on  our  iron-ware  to 
keep  the  metal  from  rusting.  It  gives  firmness  to  the 
tree  and  consistency  to  our  flesh.  It  is  the  valuable  ele- 
ment of  all  fuel,  burning  oils,  and  gases.  Thus  it  sup- 
plies our  wants  in  the  most  diverse  manner,  illustrating 
in  every  phase  the  forethought  of  that  Being  who  fitted 
up  this  world  as  a  home  for  His  children.  Infinite  Wis- 
dom alone  would  have  stored  up  such  supplies  of  fuel 
and  light,  and  hidden  them  far  under  the  earth  away 
from  all  danger  of  accidental  combustion,  or  anticipated 
the  requirements  alike  of  luxury  and  the  arts. 

Compounds.—  Carbonic  Anhydride  ,  C02- — 
Source.  —  This  gas  is  commonly  known  as  Carbonic 
Acid.  It  is  found  combined  with  Ca,  in  a  large  class  of 
salts,  known  as  the  carbonates,  viz.,  limestone,  marble, 
chalk,  etc.,  forming  nearly  one-half  of  their  weight,  and 
almost  one-seventh  of  the  crust  of  the  earth.  It  comprises 
TijJou  of  tne  atmosphere.  It  is  produced  throughout 
nature  in  immense  quantities.  Wherever  C  burns,  in 
fires,  lights,  decay,  fermentation,  volcanoes — in  a  word, 
in  all  those  various  forms  of  combustion  of  which  we 
spoke  under  the  subject  of  0,  where  that  gas  unites  with 
C,  CO 2  is  the  result.  Each  adult  exhales  daily  about  8|- 
oz.  of  carbon  changed  to  this  invisible  gas.  Each  bushel 
of  charcoal,  in  burning,  produces  not  far  from  2500  gal- 
4 


74  INORGANIC     CHEMISTRY. 

Ions.     A  lighted  candle  gives  off  about  4  gallons  pel 
hour.* 

Preparation. — For  experimental  purposes  it  is  pre- 
pared by  pouring  hydrochloric  (muriatic)  acid  on  marble 
or  chalk.  The  reaction  may  be  represented  as  follows : 


Preparing  COa.t 

The  CO 2  is  liberated  rapidly  and  may  be  gathered  by 
displacing  the  air  (see  Fig.  24),  while  the  calcium  chlo- 
ride remains  dissolved  in  the  water  of  the  flask. 

*  Burn  a  piece  of  charcoal  or  a  candle  in  a  jar  of  O.  Pour  in  a  little  lime- 
water  and  shake  it  well,  when  there  wilJ  be  a  precipitation  of  chalk  (calcium 
carbonate).  Hold  a  jar  of  air  over  a  burning  lamp  or  jet  of  coal-gas,  or  breathe 
into  the  jar  and  apply  the  test. 

t  Twist  a  wire  around  the  neck  of  a  small,  wide-mouthed  vial,  to  serve  as  a 
bucket.  Dip  the  CO3  with  it  upward  from  the  jar  and  test  with  a  lighted  match. 
Dip  the  H  (Pig.  14)  downward,  and  test  in  same  way.  This  illustrates  in  a  strik- 
ing manner  the  difference  between  the  gases  in  respect  to  specific  gravity  and 
combustion. 


CARBON.  75 

test  of  C02  is  clear  lime-water.  If  we  expose  a 
saucer  of  lime-water  to  the  air,  the  surface  of  the  solu- 
tion will  soon  be  covered  with  a  thin  pellicle  of  calcium 
carbonate  (carbonate  of  lime),  thus  showing  that  there  is 
CO 2  in  the  atmosphere ;  or  if  we  breathe  by  means  of  a 
tube  through  lime-water,  the  solution  will  become  turbid 
and  milky,  thus  proving  the  presence  of  C02  in  our 
breath :  by  breathing  through  the  liquid  a  little  longer  it 
will  become  clear,  as  the  carbonate  will  dissolve  in  an  ex- 
cess of  CO 2. 

Properties. — C02  is  a  colorless,  odorless,  transparent 
gas,  with  a  slightly  acid  taste,  and  is  a  non-supporter  of 

Fig.  25. 


Pouring  COa  down  an  inclined  plane. 

combustion.    On  account  of  its  being  heavier  than  air 
many  amusing  experiments  can  be  performed  with  it.    It 


70  INORGANIC     CHEMISTRY. 

will  run  down  an  inclined  plane,  can  be  poured  from  one 
dish  to  another,  drawn  off  by  a  syphon,  dipped  up  with  a 
bucket  like  water,  or  weighed  in  a  pair  of  scales  like 
lead. 

Mg.  26. 


Weighing  COa  with  a  pair  of  scales. 

To  show  the  C  in  C02  hold  a  strip  of  Mg  foil  in  a 
flame  until  well  ignited,  then  insert  in  a  jar  of  the  gas. 
White  flakes  of  magnesium  oxide*  (MgO)  mixed  with 
black  particles  of  charcoal  will  be  deposited. 

Asphyxia. — C02  accumulates  in  old  wells  and  cel- 
lars, where  it  has  cost  the  lives  of  many  incautious 
persons. f  The  test  of  lowering  a  lighted  candle  should 
always  be  employed.  If  that  be  extinguished,  your 
life  would  be  in  danger  of  "going  out"  in  the  same 
way,  should  you  descend.  The  gas  may  be  dipped  out 
like  water,  or  the  well  may  be  purified  by  lowering  pans 
of  slacked  lime,  or  lighted  coals  which,  when  cool,  will 
absorb  the  noxious  gas.  The  coals  may  be  re-ignited,  and 


*  These  may  be  dissolved  by  dilute  HNOS,  and  the  black  C  made  more  dis- 
tinct. 

t  "  Three  or  four  per  cent,  of  CO,  in  the  air  acts  as  a  narcotic  poison  by  pre- 
venting the  proper  action  of  the  air  upon  the  blood."— MILLER. 


CARBON.  77 

lowered  repeatedly  until  the  result  is 
reached.*  Persons  have  been  suffocated 
by  burning  charcoal  in  an  open  furnace 
in  a  closed  room.f  In  France,  it  is  not 
unusual  to  commit  suicide  in  this  manner. 
The  antidote  is  to  bring  the  sufferer  into 
the  fresh  air,  and  dash  cold  water  upon 
his  face.  In  the  celebrated  Grotto  del 
Cane,  near  Naples,  the  gas  accumulates 
upon  the  floor,  so  that  a  man  living  near  PouringliG^  °*  a 
amuses  visitors,  for  a  small  fee,  by  lead- 
ing his  dog  into  the  cave.  He  experiences  no  ill  effects 
himself,  but  the  dog  falls  senseless.  On  being  drawn  into 
the  open  air,  the  animal  soon  revives,  and  is  ready  to  pick 
up  his  bit  of  black  bread  and  enjoy  the  reward  of  his 
scientific  experiment. 

CO 2  in  Mines. — Miners  call  C02  choke-damp.  It  is 
produced  by  the  combustion  of  fire-damp  (see  p.  81), 
which  accumulates  in  deep  mines,!  and  when  mixed  with 
air,  burns  like  gunpowder,  forming  dense  volumes  of  C02, 
which  instantly  destroys  the  lives  of  all  who  may  have 
escaped  the  flames  of  the  explosion.  §  C02  has  been  used 

*  A  well,  in  which  a  candle  would  not  hum  within  twenty- six  feet  of  the  hot- 
torn,  was  thus  purified  in  a  single  afternoon. 

t  The  fumes  of  hurning  charcoal  owe  their  deadly  property  largely  to  the  pres- 
ence of  CO  (page  81),  one  per  cent,  of  which  in  the  air  causes  headache. 

$  The  word  gas  was  first  used  in  the  seventeenth  century.  Explosions,  strange 
noises,  and  lurid  flames  had  been  seen  in  mines,  caves,  etc.  The  alchemists, 
whose  earthen  vessels  often  exploded  with  tei'rific  violence,  commenced  their 
experiments  with  prayer,  and  placed  on  their  crucibles  the  sign  of  the  cross- 
hence  the  name  crucible  from  crux  (gen.  crucis),  a  cross.  All  these  manifesta- 
tions were  supposed  to  be  the  work  of  invisible  spirits,  to  whom  the  name 
ffdst  or  geist,  a  ghost  or  spirit,  was  applied.  The  miners  were  in  special  dan- 
ger from  these  unseen  adversaries,  and  it  is  said  that  their  church  service  con- 
tained the  petition,  "  From  spirits,  good  Lord,  deliver  us !"  The  names  u  spirits 
of  wine,"  "  spirits  of  nitre,"  etc.,  are  a  relic  of  the  superstitions  of  that  time. 

§  Where  COa  alone  is  found,  it  is  not  considered  as  dangerous  as  the  fire-damp, 


78  INORGANIC    CHEMISTRY. 

for  the  purpose  of  extinguishing  fires  in  coal-mines.  A 
mine  near  Sterling,  England,  had  burned  for  thirty  years, 
consuming  a  seam  of  coal  nine  feet  thick,  over  an  area  of 
twenty-six  acres.  C02,  eight  million  cubic  feet  of  which 
were  required,  was  poured  into  the  mine,  in  a  continuous 
stream,  day  and  night,  for  three  weeks.  The  mine  was 
then  cooled  with  water,  and  within  a  month  from  the 
commencement  of  the  operation  was  ready  for  the  resump- 
tion of  work. 

Absorption  of  C02  by  £iquids. — Water  dis- 
solves its  own  volume  of  C02  under  the  ordinary  pressure 
of  the  atmosphere,  forming  a  solution  of  carbonic  acid ; 
C02  +  H20  becoming  H2C03.  With  increased  pressure  a 
much  greater  amount  will  be  absorbed.  K  Soda  water " 
contains  no  soda,  but  is  simply  H20  saturated  with  C02 
in  a  copper  receiver  strong  enough  to  resist  the  pressure 
of  10  or  12  atmospheres.  The  gas  gives  the  H20  a 
pleasant,  pungent,  slightly  acid  taste,  and  by  its  escape, 
when  exposed  to  the  air,  produces  a  brisk  effervescence.* 
In  beer,  ginger-pop,  cider,  wine,  etc.,  the  C02  is  produced 
by  fermentation,  f  The  gas  escapes  rapidly  through  cider 
and  wine,  and  so  produces  only  a  sparkling ;  while  in 
a  thick,  viscid  liquid,  like  beer,  the  bubbles  are  partly 
confined,  and  hence,  cause  it  to  foam  and  froth.  In 
canned  fruits,  catsup,  etc.,  the  "  souring "  of  the  vegeta- 

Bince  it  will  not  burn,  and  it  is  said  that  miners  will  even  venture  "  where  the 
air  is  so  foul  that  the  candles  go  out,  and  are  then  re-lighted  from  the  coal  on 
the  wick  by  swinging  them  quickly  through  the  air,  when  they  burn  a  little 
while  and  then  go  out,  and  are  re-lighted  in  the  same  way." 

*  Pass  a  current  of  COa  through  a  gill  of  water.  Add  a  few  drops  of  blue  lit- 
mus-solution. It  will  immediately  redden.  Boil  the  water,  when  the  gas  will 
escape  and  the  water  become  blue. 

t  Dissolve  an  oz.  of  sugar  in  10  times  its  weight  of  water.  Put  it  in  a  flask 
like  that  shown  in  Fig.  24,  and  add  a  little  fresh  brewer's  yeast.  If  kept  warm, 
in  a  short  time  it  will  give  off  COa,  which  may  be  tested. 


CARBON.  79 

bles  produces  C02,  which  sometimes  drives  out  the  cork 
or  bursts  the  bottles  with  a  loud  report. 

Zfiquid  C02. —  By  a  pressure  of  36  atmospheres,  at 
a  temperature  of  32°,  C02  becomes  a  colorless  liquid,  very 
much  like  H20.  When  this  is  exposed  to  the  air  it  evap- 
orates so  rapidly  that  a  portion  is  frozen  into  a  snowy 
solid  which  burns  the  flesh  like  red-hot  iron.  By  means 
of  solid  C02,  Hg  can  be  readily  frozen.  When  mixed 
with  ether,  and  evaporated  under  the  exhausted  receiver 
of  an  air-pump,  a  cold  of  — 148°  may  be  produced.  (See 
Philosophy,  p.  242.) 

Ventilation .  —  The  relation  of  C02  to  life  is  most 
important,  and  cannot  be  too  often  dwelt  upon.  We  ex- 
hale constantly  this  dangerous  gas,  and  if  fresh  air  is  not 
furnished  continuously  we  are  forced  to  rebreathe  that 
which  our  lungs  have  just  expelled.*  The  languor  and 
sleepiness  we  feel  in  a  crowded  assembly,  are  the  natural 
effects  of  the  vitiated  atmosphere.  \  The  idea  of  drinking 
in  at  every  breath  the  exhalations  that  load  the  air  of  a 
crowded,  promiscuous  assembly-room,  is  a  most  disgust- 
ing one.  We  shun  impurity  in  every  form ;  we  dislike 
to  wear  the  clothes  of  another,  or  to  eat  from  the  same 
dish;  we  shrink  from  contact  with  the  filthy,  and  yet 
sitting  in  the  same  room  inhale  their  polluted  breath. 
Health  and  cleanliness  alike  require  that  we  should  care- 


*  It  is  a  fact,  as  poetical  as  it  is  characteristic,  that  when  the  air  comes  forth 
from  the  lungs  it  is  charged  with  the  seeds  of  disease ;  yet,  as  it  passes  out, 
it  produces  all  the  tones  of  the  human  voice,  all  songs,  and  prayers,  and  social 
converse.  Thus  the  gross  and  deadly  is  by  a  divine  simplicity  made  refined  and 
spiritual,  and  caused  to  minister  to  our  highest  happiness  and  welfare. 

t  It  should  be  noted  that  the  deleterious  effects  of  ill-ventilation  arise  not  only 
from  the  presence  of  CO3,  but  from  the  organic  particles  given  off  in  the  breath 
and  exhaled  from  the  skin.  (See  Physiology,  page  93.)  Kebreathed  air  is  a  fruit- 
ful source  of  consumption  and  scrofula. 


so 


INORGANIC     CHEMISTRY. 


fully  ventilate  public  buildings,  school-rooms,  and  sleep- 
ing apartments.* 

Fig.  28. 


Testing  the  currents  of  air  to  and  from  flame. 

Carbonic  Oxide,  CO,  is  a  colorless,  almost  odorless 
gas,  and  has  never  been  liquefied.  It  burns  with  a  pale 
blue  flame,  absorbing  an  atom  of  0  from  the  air,  and  be- 

*  Two  openings  are  necessary  to  ventilate  a  room.  To  illustrate  this,  Bet  a 
lighted  candle  in  a  plate  of  water,  as  shown  in  Pig.  28.  Cover  it  with  an  open 
jar,  over  the  neck  of  which  is  placed  a  common  lamp-chimney.  The  light  will 
soon  be  extinguished  on  account  of  the  consumption  of  O,  and  the  formation  of 
CO  2.  Raise  the  jar  at  one  side  a  trifle  above  the  water,  and  the  candle,  if  re- 
lighted, will  burn  steadily— fresh  air  coming  in  below,  and  the  refuse  passing  off 
at  the  top.  Replace  the  jar,  and  as  the  candle  is  flickering,  insert  in  the  chimney 
a  slip  of  card,  thus  dividing  the  passage,  when  the  light  will  brighten  again. 
Hold  a  bit  of  smouldering  touch-paper  (page  45)  at  the  top,  and  the  smoke  will 
show  two  opposite  currents  of  air  established  in  the  chimney.  Mines  have  been 
ventilated  in  this  way  by  dividing  the  shaft.  More  commonly,  however,  they 
have  two  shafts  at  a  little  distance  apart. 


CARBON. 


coming  C02.  It  is  seen  burning  thus  in  our  coal- 
stoves,  and  at  the  tops  of  tall  furnace-chimneys.  It  is 
often  formed  abundantly  on  account  of  the  action  of 
heated  carbon  on  C02.  When  air  enters  at  the  bottom 
of  a  clear  fire,  C02  is  formed  at  once  ;  but  this  gas  pass- 
ing through  the  hot  embers  takes  up  a  further  quantity 
of  C,  becoming  changed  into  CO:*  C  +  C02=2CO,  the 
carbonic  anhydride  being  exactly  doubled  in  bulk 
thereby.  CO  is  a  deadly  poison,  and  escaping  from 
coal-fires  in  a  close  room  has  often  produced  death. 
Both  CO  and  C02  leak  through  the  pores  of  cast  Fe 
when  heated,  and  still  further  injure  the  air  of  our 
houses  and  necessitate  ventilation.  The  offensive  odor 
which  comes  out  on  opening  the  door  of  our  coal-stoves 
is  caused  by  the  compounds  of  S  mixed  with  the  CO. 

M^arsh    Gas.  —  Light    Carburetted   Hydrogen,   CH4 
(see  p.  200).  —  This  we  have  already  spoken  of  under 
C02,  as  the  dreaded  fire-damp  of  miners.    It  is  colorless, 
tasteless,     odorless,     and 
burns   with    a    yellowish 
flame.      It  is  formed  in 
swamps  and  low  marshy 
places  by  the  decomposi- 
tion of  vegetable  matter, 
and  on  stirring  the  mud 
beneath  will  be  seen  bub- 
bling   up     through    the 
water.    It  may  be  collect- 
ed in  the  manner  shown 


Fig. 


Colkctin<> 


*  This  fact  is  of  great  importance,  since  thereby  much  heat  is  wasted.  Stoves 
are  sometimes  so  constructed  as  to  admit  fresh  air  just  above  the  grate,  thus 
consuming  this  gas. 


INORGANIC    CHEMISTRY. 


in  Fig.  29.  It  rises  from 
the  earth  in  great  quanti- 
ties at  many  places.  At 
Fredonia,  N.  Y.,  it  is  used 
in  lighting  the  Tillage.  At 
Kanawha,  Va.,  it  was  until 
lately  employed  as  fuel  for 
evaporating  the  brine  in 
the  manufacture  of  salt. 
In  the  oil-wells  of  Penn- 
sylvania, it  frequently 
bursts  forth  with  explosive 
violence,  throwing  the  oil 
high  into  the  air. 

O2efiant  Gas.- 
Heavy  Carluretted  Hy- 
drogen, C2H4.  — This  is 
a  colorless  gas,  with  a 
sweet,  pleasant  odor,  and 
burns  with  a  clear  white 
light.*  It  may  be  easily 
prepared  by  heating  in  a 
large  retort  a  mixture  of 
one  part  of  alcohol  with 
two  of  H2S04. 

Coa2  Gas  is  a  very 
variable  mixture.  The 


*  Fill  a  tall  iar  one-third  full  of 
defiant  gas,  and  the  remainder  with 
chlorine  gas.  On  lighting,  the  mix- 
ture will  burn  with  a  dense  cloud  of 
smoke.  HC1  is  the  product  of  tho 
combustion. 


Manufacture  of  Coal-gas. 


CARBON.  83 

proportion  of  olefiant  gas  and  hydrocarbons  having  a 
similar  composition  gives  whiteness  to  the  flame ;  while 
the  H  and  CH4  have  little  illuminating  power,  and  serve 
mainly  as  carriers  of  the  more  valuable  gases  (MILLER). 
Bituminous  coal  is  heated  in  large  iron  retorts,  B,  until 
only  coke  is  left  and  the  volatile  constituents  are  driven 
off.  Among  them  are  coal-tar,  H3N,  C02,  CO,  N,  com- 
pounds of  S,  CH4,  and  C2H4.*  This  mixture  is  led 
through  the  curved  pipes,  d,  beneath  the  H20  in  the  hy- 
draulic main,  F ;  along  the  tube,  g,  to  the  tar  cistern  j 
thence  up  and  down  the  condenser,  j.  On  the  way  it  be- 
comes cooled  and  loses  its  coal-tar,  ammoniacal  salts,  f 
and  liquid  hydrocarbons.  Lastly  it  is  passed  over  lime, 
Lm,  which  absorbs  the  C02  and  the  H2S.J;  The  remain- 
ing gases  form  the  mixture  we  call  "  gas."  This  is  col- 
lected in  the  gasometer,  P,  the  weight  of  which  forces  it 
through  all  the  little  gas-pipes,  and  up  to  every  jet  in  the 
city.  . 

Coal-gas  is  very  poisonous,  and  even  in  small  quantities 
exceedingly  deleterious.  When  mixed  with  air  it  ex- 
plodes with  great  violence.  Its  unpleasant  odor,  though 
often  annoying,'  is  a  great  protection,  as  we  are  thereby 
warned  of  its  presence. 

Cyanogen,^  Cy=CN. — Preparation. — As   N  and  C 

*  None  of  these  substances  exists  in  coal.  They  are  formed  by  the  action  of 
heat,  which  causes  the  H,  C,  O,  N  and  S  to  combine  and  make  a  multiplicity  of 
compounds. 

t  The  H3N  is  neutralized  by  HC1,  thus  forming  chloride  of  ammonium  (pal- 
ammoniac,  H4N,C1).  On  evaporation,  the  tough,  fibrous  crystals  of  the  salt  are 
obtained.  (See  page  135.) 

t  The  removal  of  the  sulphur  compounds  is  especially  important,  since,  when 
burned,  they  furnish  sulphurous  and  sulphuric  acids,  which  are  very  injurious  to 
books,  paintings,  and  furniture. 

§  The  term  cyanogen  means  "  blue  producer ;"  this  gas  being  the  character- 
istic constituent  of  Prussian  blue. 


84  INORGANIC    CHEMISTRY. 

do  not  combine  directly,  this  gas  is  obtained  in  an  in- 
direct way.  Mix  the  parings  of  horns,  hides,  etc.,  with 
pearlash  (potassium  carbonate)  and  iron  filings,  and  heat 
in  a  close  vessel.  The  N  and  C  of  the  animal  substances, 
in  their  nascent  state,  will  combine,  forming  Cy ;  this 
uniting  with  the  Fe  and  K  will  produce  the  beautiful  yel- 
low crystals  of  potassium  ferro-cyanide  (yellow  prussiate 
of  potash).  From  this  salt  the  mercury  cyanide  is  made, 
which  when  heated  decomposes  into  Hg  and  Cy. 

Properties. — Cy  is  a  transparent,  colorless  gas,  with  a 
penetrating  odor.  It  burns  with  a  characteristic  rose- 
edged  purple  flame,  and  is  exceedingly  poisonous.  It  is 
very  interesting  from  the  fact  that,  though  a  compound, 
it  unites  directly  with  the  metals  like  the  elements  I,  B, 
etc.  It  is  therefore  called  a  compound  radical  (root). 
"We  shall  find  this  subject  of  great  importance  in  Organic 
Chemistry. 

Jfydrocyanic  Acid,  HCy.  —  Prussic  acid,  as  it  is 
commonly  called,  is  a  fearful  poison.  A  single  drop  on 
the  tongue  of  a  large  dog  is  said  to  produce  instant  death. 
H3N,  cautiously  inhaled,  is  its  antidote.  Its  bitter  flavor 
is  detected  in  peach  blossoms,  the  kernels  of  plums  or 
peaches,  bitter  almonds,  and  the  leaves  of  wild  cherry. 

J^u2minic  Acid  (fulmen,  a  thunderbolt). — This 
compound  of  Cy  is  known  only  as  combined  with  the  va- 
rious metals  forming  fulminates,  which  are  remarkably 
explosive.  Fulminating  mercury  was  used  to  fill  the 
bombs  with  which  the  life  of  Napoleon  III.  was  attempt- 
ed in  1858.  It  is  employed  in  making  gun-caps.  A  drop 
of  gum  is  first  put  in  the  bottom  of  the  cap,  over  which 
is  sprinkled  a  little  fulminating  mercury,  and  this  is 


CARBON.  85 

sometimes  covered  with  varnish  to  protect  it  from  any 
moisture. 


COMBUSTION. 

COMBUSTION,  in  general,  is  the  rapid  union  of  a  sub- 
stance with  0,  and  is  accompanied  by  heat  and  light* 

The  Igniting  *Point  of  any  substance  is  the  tem- 
perature at  which  "it  catches  fire."  "We  elevate  the 
heat  of  a  small  portion  to  the  point  of  rapid  union  with 
0,  and  that  part  in  burning  will  give  off  heat  enough  to 
support  the  combustion  of  the  rest. — Example :  In  mak- 
ing a  fire,  we  take  paper  or  shavings,  which  being  poor 
conductors  of  heat,  and  exposing  a  large  surface  to  the 
action  of  0,  are  easily  raised  to  the  required  temperature. 
Having  thus  obtained  sufficient  heat  to  start  the  combus- 
tion of  chips  or  pine  sticks,  we  gradually  increase  it  until 
there  is  enough  to  ignite  the  coal  or  wood. 

Chemistry  of  a  Fire.  —  Our  fuel  and  lights,  such 
as  wood,  coal,  oil,  tallow,  etc.,  consist  mainly  of  C  and 
H,  and  are,  therefore,  called  hydrocarbons.  In  burn- 
ing they  unite  with  the  0  of  the  air,  forming  H20 
and  CO  2.  These  both  pass  off,  the  one  as  a  vapor,  the 
other  as  a  gas.  In  a  long  stove-pipe,  the  H20  is  some- 
times condensed,  and  drips  down,  bringing  soot  upon  our 
carpets.  Ashes  comprise  the  mineral  matter  contained 
in  the  fuel,  united  with  some  of  the  C02  produced  in  the 
fire.  When  we  first  put  fuel  in  the  stove,  the  H  is  liber- 
ated with  some  C,  in  the  form  of  marsh  or  olefiant  gas, 

*  There  are  forms  of  combustion  known  to  the  chemist  which  are  not  oxida- 
tion ;  as  the  union  of  S  and  Cu.    (See  page  97,  note.) 


86 


INORGANIC    CHEMISTRY. 


This  burns  with  a  flame.  Then,  the  volatile  H  haying 
passed  on0,  we  have  left  the  C,  which  burns  as  coal 
merely.  In  maple  there  is  much  more  C  than  in  pine,  so 
it  forms  a  good  "  bed  of  coals/'  In  the  burning  of  fuel 
there  is  no  annihilation;  but  the  H20,  C02,  and  the 
ashes,  weigh  as  much  as  the  wood  and  the  0  that  com- 
bined with  it.  No  matter  how  rapidly  the  fire  burns, 
even  in  the  blaze  of  the  fiercest  conflagration,  the  ele- 
ments unite  in  exact  atomic  weights. 

C  is  most  wisely  fitted  for  fuel,  since  the  product  of 
its  combustion  is  a  gas.  Were  it  a  solid,  our  fires  would 
be  choked,  and  before  each  supply  of  fresh  fuel  we 
should  be  compelled  to  remove  the  ashes.  In  the  case 
of  a  candle  or  lamp  it  would  be  still  more  annoying, 
as  the  solid  product  would  fall  around  our  rooms. 
Still  another  useful  property  is  the  infusi- 


application  of  heat,  how  quickly  in  a  hot  fire 
would  the  coal  and  wood  run  down  through 
the  grate  and  out  upon  the  floor  in  a  liquid 
mass ! 

Chemistry  of  a  Candle. — Flame  is 
burning  gas.  A  candle  is  a  small  "  gas-work," 
and  its  flame  is  the  same  as  that  of  a  "  gas- 
burner."  First,  we  have  a  little  cupful  of  tal- 
low melted  by  the  heat  of  the  fire  above.  The 
ascending  currents  of  cool  air  which  supply 
the  light  with  0  also  keep  the  sides  of  the  cup 
hard,  unless  the  wind  blows  the  flame  down- 
ward, when  the  banks  break,  there  is  a  crevasse,  and  our 
"  candle  runs  down."  Next,  the  melted  tallow  is  carried 
by  capillary  attraction  up  the  small  tubes  of  the  wick  into 


Form  of 
flame. 


COMB  USTION. 


87 


the  flame.  There  it  is  turned  into  gas  by  the  heat. 
Flame  is  always  hollow,  and  at  the  center,  near  the  wick, 
is  the  gas  just  formed.  If  a  match  be  placed  across  a 
light,  it  will  burn  off  at  each  side,  in  the  ring  of  the 
flame,  while  the  center  will  be  unblackened.*  The 
gas  may  be  conducted  out  of  the  flame  by  a  small 
pipe,  and  burned  at  a  little  distance  from  the  can- 
dle. Flame  is  hollow  because  there  is  no 
0  al  the  center.  The  gas  floats  outward  Mg' 22' 

from  the  wick.  It  comes  in  contact  with 
the  0  of  the  air,  and  the  H,  requiring 
least  heat  to  unite,  burns  first,  forming 
H20.  This  produces  heat  enough  to 
make  the  tiny  particles  of  C,  floating 
around  in  the  flame  of  burning  H,  white- 
hotf  They  each  send  out  a  delicate 
wave  of  light,  and  passing  on  to  the 
outer  part,  where  there  is  more  0,  burn, 
forming  C02-  The  flame  is  blue  at  the 
bottom,  because  there  is  so  much  0  at 
that  point  that  the  H  and  0  burn  to- 
gether, and  so  give  little  light.  The  H20 
may  be  condensed  on  any  cold  surface. 
The  CO 2  may  be  tested  by  passing  the  invisible  vapor  of 
a  candle  through  lime-water.  The  wick  of  a  candle  does 
not  burn  because  of  the  lack  of  0  at  the  center.  It,  how- 

*  Take  a  sheet  of  white  paper  and  thrust  it  quickly  down  upon  the  flame  of  a 
candle  or  lamp.  It  will  burn  in  a  ring,  and  when  the  paper  is  removed  the  cen- 
ter will  be  found  unblackened. 

t  Frankland  has  shown  that  the  intensity  of  a  flame,  in  general,  is  determined 
by  the  density  of  the  gas :  thus  a  jet  of  H  burning  under  a  pressure  of  ten 
atmospheres  will  furnish  sufficient  light  to  read  a  newspaper  at  a  distance  of 
two  feet. 


Match  in  flame;  the 
S  and  P  being  un- 
consumed. 


88 


INORGANIC    CHEMISTRY. 


ever,  is  charred,  as  all  the  volatile  gas  is  driven  off  by  the 
heat.    If  a  portion  falls  over  to  the  outer  part,  where 

Fig.  SS. 


Testing  the  COa  of  aflame  by  drawing  the  gas  through  lime-water. 

there  is  0,  it  burns  as  a  coal.  If  we  blow  out  a  candle 
quickly,  the  gas  still  passes  off,  and  we  can  relight 
it  with  an  ignited  match  held  at  some  distance  from 
the  wick.  The  tapering  form  of  the  flame  is  due  to  the 
currents  of  air  that  sweep  up  from  all  sides  toward  it. 
The  candle  must  be  snuffed,  because  the  long  wick  would 
cool  the  blaze  below  the  igniting  point  of  C  and  0,  and 
the  C  would  pass  off  unconsumed.  A  draught  of  air,  or 
any  cold  substance  thrust  into  the  flame,  produces  the 
same  result,  and  deposits  the  C  as  soot.  Plaited  wicks 
are  sometimes  used,  which,  being  thin,  fall  over  to  the 
outside  and  burn,  requiring  no  snuffing. 

Chemistry  of  a  Z/amp .  —  A  chimney  confines  the 
hot  air,  and  makes  a  draught  of  heated  0  to  feed  the 


COMB  U  S  TIO  N. 


89 


Fig.  35. 


flame.    A  flat  wick  is  used,  as  it  &&•  sit. 

presents  more  surface  to  the  ac- 
tion of  the  0.  Argand  lamps 
have  a  hollow  wick  which  admits 
0  into  the  center  of  the  blaze. 
The  film  which  gathers  on  a  chim- 
ney when  we  first  light  a  lamp, 
is  the  H  20  produced  in  the  flame, 
condensed  on  the  cold  glass.  A 

HaO  condensed  from  aflame. 

pint  of  oil  forms  a  full  pint  of 

H20.  Spirits  of  turpentine,  tar,  pine-wood,  etc.,  con- 
tain an  excess  of  C,  and  not  enough  H  to  heat  it  to 
the  igniting  point.  These,  there- 
fore, produce  clouds  of  soot.  Alco- 
hol contains  an  excess  of  H  and  little 
C,  hence  it  gives  off  great  heat  and 
little  light. 

1)ary?  s  Safety  Z,amp,  used 
by  miners,  consists  of  an  ordinary 
oil-lamp,  surrounded  by  a  cylinder 
of  fine  wire-gauze.  When  it  is  car- 
ried into  an  atmosphere  containing 
the  dreaded  fire-damp,  the  flame  en- 
larges and  becomes  pale,  and  when 
the  quantity  increases,  the  gas  will 
quietly  burn  on  the  inside  of  the 
cylinder.*  There  is  no  danger  of 
an  explosion  so  long  as  the  gauze 


Davy's  Safety  Lamp, 


*  The  principle  of  the  lamp  can  be  illustrated  by  holding  a  fine  wire-gauze 
over  the  flame  of  a  candle  or  lamp  (Fig.  36).  The  flame  will  not  piss  through, 
since  the  wire  will  conduct  away  the  heat  and  so  reduce  the  tempe^ture  below 
the  igniting  point.  A  jet  of  gas,  issuing  at  a  low  temperature,  m^  be  lighted 
on  either  side  of  the  gauze  at  pleasure. 


INORGANIC    CHEMISTRY. 


Win  gauze  over  flame. 


Fig.  37 


remains  perfect*  Through  carelessness,  however,  fearful 
accidents  haye  occurred.  Miners  become 
extremely  negligent,  and  an  account  is 
given  of  an  explosion,  in  which  about  a 
hundred  persons  were  killed,  caused  by 
a  lamp  being  hung  on  a  nail  by  a  hole 
broken  through  the  wire-gauze. 

tBunsen's  ^Burner  is  used  in  the 
laboratory.    It  consists  of  a  jet  of  gas, «, 

surrounded  by  a  metal  tube,  c,  at  the  bottom  of  which  are 

openings,  #,  for  the  admission  of  air.    The  gas  passes  up 

the  tube,  mingles  with 

the   air,    and    burns 

at    the  top    without 

smoke.      The    0    is 

supplied  in  sufficient 

quantity  to  burn  the 

H  and  C  simultane- 
ously ;  hence  there  is 

great  heat  with  little 

light  and  no  smoke. 
The  Oxy-?iydro- 

gen  3$2ow-})ifle  is 

so    constructed    that 

a  jet  of  0  is  intro- 

duced  into  the  center 

of  one  of  burning  H, 

thus  producing  a  solid 

flame.    A  watch-spring  will  burn  in  it  with  a  shower  of 


Eunsen's  burner. 


*  At  such  a  time,  however,  the  wise  miner  will  leave  the  place  of  danger,  lest 
the  metal  should  melt  and  the  fire  escape  to  the  gas,  when  an  explosion  would 


COMB  USTIO  N. 


91 


sparks.      Pt,  the  most  infusible  of  metals,  will  readily 
melt.    In  the  common  flame,  as  we  ha7e  seen,  the  little 

Mg.38. 


The  Oxy-hydrogen  Blow-pipe. 

particles  of  solid  C,  heated  by  the  burning  H,  produce 
the  light.  As  there  is  no  solid  body  in  the  blow-pipe 
flame,  it  is  scarcely  luminous.  If,  however,  we  insert  in 
it  a  bit  of  CaO,  or  MgO,  a  dazzling  light  is  produced. 
This  is  called  the  "Drummond,"  "Lime/'  or  "Calcium" 


INORGANIC    CHEMISTRY. 


Fig.  39. 


Light,  and  with  a  properly  arranged  reflector  has  been 
seen  at  a  distance  of  one  hundred  and  eight  miles  in 
broad  sunlight. 

Moutfi  322ow-flipe. — In  the  com- 
mon blow-pipe,  used  by  jewelers  and 
mineralogists,  a  current  of  air  from  the 
lungs  is  thrown  across  the  light  just 
above  the  wick.  The  flame  loses  its 
brilliancy  and  is  driven  one  side  in  the 
form  of  a  cone  (Fig.  40).  Three  parts 
are  clearly  visible.  In  the  center  is  a 
blue  cone  ending  at  a  ;  outside  of  this 
is  a  whiter  and  more  luminous  one  ter- 
minating at  1)  ;  and  beyond  this  a  pale 
yellow  flame,  c.  The  blue  cone  is 
caused  by  the  excess  of  0  from  the 
blow-pipe  burning  the  C  and  H  at  the 
same  time.  The  luminous  cone  con- 
tains C  in  excess,  which  being  heated 
gives  out  light.  The  combustible  vapor 
at  this  point,  hot  and  ready  to  com- 
bine, will  take  0  from  any  substance  exposed  to  it,  and 
is  therefore  called  the  reducing  flame.  The  outer  en- 


Oommon  Slow-pipe. 


velope  contains  the  0  thrown  from  the  lungs,  borne  for- 
ward by  the  jet  of  flame,  and  highly  heated  by  it.    It  will 


COMBUSTION.  93 

unite  with  a  metallic  body,  and  is  therefore  called  the 
oxidizing  flame. — Example:  Hold  a  copper  cent  in  the 
blaze  of  an  alcohol  lamp ;  in  the  "  reducing  flame  "  its 
rust,  copper  oxide,  will  be  cleaned  off,  and  the  metal  will 
shine  as  brightly  as  if  just  from  the  mint.  In  the  "  oxi- 
dizing flame  "  a  film  of  copper  oxide  will  be  formed  over 
the  surface,  and  as  we  move  the  cent  the  most  beautiful 
play  of  colors  will  flash  from  side  to  side.* 

jEfxtinguiskmg  Fires.  —  Blowing  on  a  candle  or 
lamp  extinguishes  it,  because  it  lowers  the  heat  of  the 
flame  below  the  igniting  point  of  the  gases,  f  Fires  are 
put  out  by  H20  partly  for  the  same  reason,  and  also  be- 
cause it  envelops  the  wood  and  shuts  off  the  air.  If  a 
person's  clothes  take  fire,  the  best  course  is  to  wrap  him 
in  a  blanket,  carpet,  coat,  or  even  in  his  own  garments. 
This  smothers  the  fire  by  shutting  out  the  0.  Great  care 
should  be  taken  in  a  fire  not  to  open  the  doors  or  win- 
dows, so  as  to  cause  a  draught  of  air.  The  entire  build- 
ing may  burst  into  a  blaze,  when  the  fire  might  have 
languished  for  want  of  0,  and  so  have  been  easily  ex- 
tinguished. 

Spontaneous  Combustion.  —  Sometimes  chemical 
changes  take  place  in  combustible  substances,  whereby 
heat  enough  is  generated  to  cause  ignition.  CaO  occa- 
sionally absorbs  H20,  so  as  to  set  fire  to  wood  in  contact 
with  it.  Fresh-burned  charcoal  has  the  power  of  absorb- 
ing gases  .in  its  pores  so  rapidly  as  to  become  ignited. 

*  Introduce  a  small  piece  of  common  flint-glass  tube  into  the  reducing  flame. 
The  glass  will  become  opaque  and  black,  because  the  Pb  will  be  reduced  from 
the  transparent  form  of  oxide  to  the  opaque  condition  of  metal.  When  this  has 
happened,  place  the  black  portion  just  in  front  of  the  oxidizing  flame.  The  dis- 
coloration will  slowly  disappear,  and  the  Pb  will  recombine  with  O  from  the  air 
and  the  glass  again  become  transparent. 

t  Sometimes,  also,  the  flame  is  driven  off  by  the  mere  force  of  the  breath. 


'94  INORGANIC     CHEMISTRY. 

Heaps  of  coal  take  fire  from  the  iron  pyrites  contained  in 
them,  which  is  decomposed  by  the  moisture  of  the  air. 
The  waste  cotton  used  in  mills  for  wiping  oil  from 
the  machinery,  when  thrown  into  large  heaps,  often  ab- 
sorbs 0  from  the  air  so  rapidly  that  it  bursts  into  a  blaze. 

PRACTICAL    QUESTIONS. 

1.  Why  does  not  blowing  cold  air  on  a  fire  with  a  bellows  ex- 
tinguish it  ? 

2.  Why  will  pine-wood  ignite  more  easily  than  maple  ? 

3.  Why  is  fire-damp  more  dangerous  than  choke-damp  ? 

4.  Represent  the  reaction  in  making  C02,  showing  the  atomic 
weights,  as  in  the  preparation  of  O  on  page  28. 

5.  Should  one  take  a  light  into  a  room  where  the  gas  is  escap- 
ing? 

6.  What  causes  the  difference  between  a  No.  1  and  a  No.  4 
pencil? 

7.  Why  does  it  dull  a  knife  to  sharpen  a  pencil  ? 

8.  Why  is  slate  found  between  seams  of  coal  ? 

9.  Why  was  the  coal  hidden  in  the  earth  ? 

10.  Where  was  the  C,  now  contained  in  the  coal,  before  the  Car- 
boniferous age  ? 

11.  Must  the  air  have  then  contained  more  plant  food  ?    (p.  98.) 

12.  What  is  the  principle  of  the  aquarium  ? 

13.  What  test  should  be  employed  before  going  down  into  an  old 
well  or  cellar  ? 

14.  What  causes  the  sparkle  of  wine,  and  the  foam  of  beer? 

15.  What  causes  the  cork  to  fly  out  of  a  catsup  bottle  ? 

16.  What  philosophical  principle  does  the  solidification  of  C02 
illustrate  ? 

17.  Why  does  the  division  in  the  chimney  shown  in  Fig.  28  pro- 
duce opposite  currents  ? 

18.  What  causes  the  unpleasant  odor  of  coal-gas  ?    Is  it  useful  V 

19.  What  causes  the  sparkling  often  seen  in  a  gas-light  ? 

20.  Why  does  H  in  burning  give  out  more  heat  than  C  ? 

21.  Why  does  blowing  on  a  fire  kindle  it,  and  on  a  lighted  lamp 
extinguish  it  ? 

22.  Why  can  we  not  ignite  hard  coal  with  a  match  ? 


COMBUSTION.  95 

23.  What  causes  the  dripping  of  a  stove-pipe  ? 

24.  Why  will  an  excess  of  coal  put  out  a  fire  ? 

25.  Why  do  not  stones  burn  as  well  as  wood  ? 

26.  Why  does  not  hemlock  make  "  a  good  bed  of  coals  ?  " 

27.  What  adaptation  of  chemical  affinities  is  shown  in  a  light  ? 

28.  Is  there  a  gain  or  a  loss  of  weight  by  combustion  ? 

29.  Why  does  snuffing  a  candle  brighten  the  flame  ? 

30.  Why  is  the  flame  of  a  candle  red  or  yellow,  and  that  of  a 
kerosene  oil-lamp  white  ? 

31.  Why  is  it  beneficial  to  stir  a  wood-fire,  but  not  one  of  anthra- 
cite coal  ? 

32.  Why  will  water  put  out  a  fire  ? 

33.  What  should  we  do  if  a  person's  clothes  take  fire  ? 

34.  Ought  the  doors  of  a  burning  house  to  be  thrown  open? 

35.  Why  does  a  street  gas-light  burn  blue  on  a  windy  night  ?    Is 
the  light  then  as  intense  ?    The  heat  ? 

36.  Why  does  not  the  lime  burn  in  a  calcium-light  ? 

37.  Why  is  a  candle-flame  tapering  ? 

38.  Why  does  a  draught  of  air  cause  a  light  to  smoke  ? 

39.  What  makes  the  coal  at  the  end  of  a  candle-wick  ? 

40.  Which  is  the  hottest  part  of  a  flame  ? 

41.  Why  does  not  a  candle-wick  burn? 

42.  How  does  a  chimney  enable  us  to  burn  without  smoke  highly 
carboniferous  substances  like  oil  ? 

43.  How  much  C02  in  200  Ibs.  of  chalk  ? 

44.  What  weight  of  C02  in  a  ton  of  marble  ? 

45.  What  is  the  difference  between  marble  and  chalk?     (See 
page  139.) 

46.  Why  does  not  a  cold  saucer  held  over  an  alcohol  flame  blacken, 
as  it  does  over  a  candle  or  gas-light  ? 

47.  Could  a  light  be  frozen  out,  i.  e.,  extinguished,  by  merely  low- 
ering the  temperature  ? 

48.  How  much  C02  is  formed  in  the  combustion  of  one  ton  of  C  ? 

49.  What  weight  of  C  is  there  in  a  ton  of  C02  ? 

50.  How  much  O  is  consumed  in  burning  a  ton  of  C  ? 

51.  What  weight  of  sodium  carbonate  (Na2C03,  "  carbonate  of 
soda")  would  be  required  to  evolve  12  Ibs.  of  C02  ? 

52.  How  much  C02  will  be  formed  in  the  combustion  of  30  grs. 
of  CO? 

53.  What  weight  of  hydrogen  sodium  carbonate  (HNaC03,  "bi- 
carbonate of  soda  ")  would  be  required  to  evolve  12  Ibs.  of  COS  ? 


96  IXORQANIC    CHEMISTRY. 

54.  Write  in  double  columns  the  different  properties  of  carbonic 
anhydride  and  carbonic  oxide ;  thus, 

CO,  is  I  CO  is 

1,  non-inflammable.  I  1,  inflammable. 


THE    ATMOSPHERE. 

The  "air  we  breathe  "  consists  of  N,  0,  C02,  and  watery 
vapor.  The  first  composes  f,  the  second  J,  the  third 
about  7s,t)u<jj  and  the  last  a  variable  amount.*  A  very 
clear  idea  of  the  proportion  of  these  several  constituents 
may  be  formed  by  conceiving  the  air,  not  as  now  dense 
near  the  surface  of  the  earth,  and  gradually  becoming 
rarefied  as  we  ascend  to  its  extreme  limit  of  perhaps  500 
miles,  but  of  a  density  throughout  equal  to  that  which 
it  now  possesses  near  the  earth.  The  atmosphere  would 
then  be  about  five  miles  high.  The  vapor  would  form  a 
sheet  of  H20  over  the  ground  five  inches  deep,  next  to 
this  the  CO 2  a  layer  of  13  feet,  then  the  0  a  layer  of  one 
mile,  and  last  of  all  the  N  one  of  four  miles. — GRAHAM. 
In  this  arrangement  we  have  supposed  the  gases  to 
be  placed  in  the  order  of  their  specific  gravity.  The 
atmosphere  is  not  thus  composed  in  fact,  the  various 
gases  being  equally  mingled  throughout,  in  accordance 
with  a  principle  called  the  "  Law  of  the  diffusion  of 
Gases"  If  we  throw  a  piece  of  lead  into  a  brook,  it  will 
settle  instantly  to  the  b.ottom  by  the  law  of  gravitation, 
and  will  remain  there  by  the  law  of  inertia.  But  if  we 
throw  into  the  atmosphere  a  quantity  of  C02,  it  will 
sink  for  an  instant,  then  immediately  begin  to  mingle 

*  The  N  and  0  form  so  large  a  part,  that  they  are  considered  in  ordinary  cal- 
culation to  compose  the  whole  atmosphere. 


THE    ATMOSPHERE.  97 

with  the  surrounding  air,  and  soon  become  dissipated. — 
Example :  If  we  invert  an  open-mouthed  bottle  full  of  H 
over  another  full  of  C02,  the  H,  light  as  it  is,  will 
sink  down  into  the  lower  jar;  and  the  C02, 
heavy  as  it  is,  will  rise  into  the  upper  jar; 
and  in  a  few  hours  the  gases  will  be  found 
equally  mixed.  By  this  law  the  proportion  of 
the  elements  of  the  atmosphere  is  the  same  every- 
where, and  has  not  varied  within  historic  times. 
Samples  have  been  analyzed  from  every  conceiva- 
ble place,  from  polar  and  torrid  regions,  from 
prairies  and  mountain-tops,  from  balloons  and 
mines,  from  crowded  capitals  and  lonesome  for- 
ests, and  even  from  bottles  found  sealed  up  in  the 
ruins  of  Herculaneum,  and  the  result  is  almost 
exactly  the  same.  These  gases  do  not  form  a 


S 


chemical  compound,  but  a  mere  mechanical  mix-      gases. 
ture,*  and  they  are  as  distinct  in  the  air  as  so  many  grains 
of  wheat  and  corn  mingled  in  a  measure. 

Each  of  the  constituents  of  the  air  has  its  separate  use 
and  mission.  The  action  of  0  and  N  we  have  already 
seen. 

Uses  of  C02. — Carbonic  acid  bears  the  same  relation 
to  Vegetable  that  0  does  to  animal  life.  The  leaf — the 

*  "  To  illustrate  the  difference  between  a  mechanical  mixture  and  a  chemical 
compound,  mix  powdered  S  and  filings  of  Cu.  The  color  of  the  S  as  well  as  that 
of  the  Cu  will  disappear,  and  to  the  unaided  eye  will  present  a  uniform  greenish 
tint ;  with  the  microscope,  however,  the  particles  of  Cu  may  be  seen  lying  by 
the  side  of  those  of  S  ;  and  we  can  wash  away  the  lighter  S  with  H2O,  leaving 
the  heavier  Cu  behind.  Here  no  rfamical  action  has  occurred ;  the  S  and  Cu 
were  only  mechanically  mixed.  If  we  next  gently  heat  some  of  the  mixture  it 
soon  begins  to  glow,  and  on  examining  the  mass  we  find  that  both  the  Cu  and 
the  S  have  disappeared  as  such,  that  they  cannot  be  distinguished  even  with  the 
most  powerful  microscope,  and  that  in  their  place  we  have  formed  a  black  sub- 
stance possessing  properties  entirely  different  from  those  possessed  either  by  the 
Cu  or  the  S."— BOSCOE. 

5 


98  INORGANIC     CHEMISTRY. 

plant-lungs — through  its  million  of  little  stomata,  or 
mouths,  drinks  in  the  C02.  In  that  minute  leaf -labora- 
tory, by  the  action  of  the  sunbeam,  the  C02  is  decom- 
posed,* the  C  being  applied  to  build  up  the  plant,  and 
the  0  returned  to  the  air  for  our  use.  Plants  breathe  out 
0  as  we  breathe  out  CO 2.  We  furnish  vegetables  with 
air  for  their  use,  and  they  in  turn  supply  us.  There  is 
thus  a  mutual  dependence  between  the  animal  and  the 
vegetable  world.  Each  relies  upon  the  other.  Deprived 
of  plants  we  should  soon  exhaust  the  0  from  the  air, 
supply  its  place  with  C02,  and  die ;  while  they,  removed 
from  us,  would  soon  exhaust  the  C02,  and  die  as  cer- 
tainly. We  pollute  the  air  while  they  purify  it.  Each 
tiny  leaf  and  spire  of  grass  is  thus  imbibing  our  foul 
breath,  and  returning  it  to  us  pure  and  fresh. f  This  in- 


*  "  In  order  to  decompose  carbonic  acid  in  our  laboratories,  we  are  obliged  to 
resort  to  the  most  powerful  chemical  agents,  and  to  conduct  the  process  in  ves- 
sels composed  of  the  most  resisting  materials,  under  all  the  violent  manifesta- 
tions of  light  and  heat,  and  we  then  succeed  in  liberating  the  carbon  only  by 
shutting  up  the  oxygen  in  a  still  stronger  prison  ;  but  under  the  quiet  influences 
of  the  sunbeam,  and  in  that  most  delicate  of  all  structures,  a  vegetable  cell,  the 
chains  which  unite  together  the  two  elements  fall  off,  and,  while  the  solid  car- 
bon is  retained  to  build  up  the  organic  structure,  the  oxygen  is  allowed  to 
return  to  its  home  in  the  atmosphere.  There  is  not  in  the  whole  range  of  chem- 
istry a  process  more  wonderful  than  this.  We  return  to  it  again  and  again,  with 
ever  increasing  wonder  and  admiration,  amazed  at  the  apparent  inefficiency  of 
the  means,  and  the  stupendous  magnitude  of  the  result.  When  standing  be- 
fore a  grand  conflagration,  witnessing  the  display  of  mighty  energies  there  in 
action,  and  seeing  the  elements  rushing  into  combination  with  a  force  which 
no  human  agency  can  withstand,  does  it  seem  as  if  any  power  could  undo  that 
work  of  destruction,  and  rebuild  those  beams  and  rafters  which  are  disappear- 
ing in  the  flames  ?  Yet  in  a  few  years  they  will  be  rebuilt.  This  mighty  force 
will  be  overcome  ;  not,  however,  as  we  might  expect,  amidst  the  convulsion  of 
nature,  or  the  clashing  of  the  elements,  but  silently,  in  a  delicate  leaf  waving 
in  the  sunshine."— COOKE. 

t  Prom  this  statement  it  is  evident  that  the  foliage  of  house-plants  must  be 
healthful.  Moreover,  there  is  some  reason  to  believe  that  the  O  which  they  ex- 
hale is  highly  ozonized,  and  therefore  of  great  value  in  destroying  miasmic 
germs.  We  should  remember,  however,  that  flowers  exhale  COa ;  and  the  odor 
of  certain  plants,  and  the  pollen  of  others,  are  very  injurious.  Plants  and 
flowers,  which  to  one  person  are  innocuous,  are  to  another  detrimental.  Thus 


THE    ATMOSPHERE. 
Fig.  1#. 


99 


Apparatus  arranged  to  catch  Hie  O  evolved  from  a  sprig  of  leaves. 

terchange  of  office  is  so  exactly  balanced,  that,  as  we  have 
seen,  the  proportion  of  C02  and  of  0,  in  the  open  air, 
never  varies.* 


the  fragrance  of  new-mown  grass,  which  is  so  agreeable  to  some,  produces  in 
others  what  is  termed  the  hay-fever  ;  due,  it  is  said,  to  the  pollen  of  the  grass. 
Each  family,  therefore,  must  determine  for  itself  what  should  he  excluded  from 
its  collection.  It  is  evident  that  flowerless  plants,  like  the  ivy,  etc.,  are  harm- 
less, while  the  cheerfulness  given  to  an  apartment  by  even  a  few  pots  of  flowers 
on  a  window-bench,  should  induce  one  to  take  some  trouble  in  order  to  make  a 
selection  which  will  not  only  beautify  but  purify  the  room. 

*  "Two  hundred  million  tons  of  coal  are  now  annually  burned,  producing  six 
hundred  million  tons  of  CO2.  A  century  ago,  hardly  a  fraction  of  that  amount 
was  burned,  yet  this  enormous  aggregate  has  not  changed  the  proportion  in  the 
least."— YOUMANS. 


100  INORGANIC     CHEMISTRY. 

(PZants  Store  up  Solar  Force.  —  The  sunbeam, 
which  is  thus  strong  enough  to  wrench  apart  the  C  and 
0,  sends  out  the  0  full  of  potential  force,  and,  by  its 
energy,  builds  up  the  plant.  The  force  of  the  sunbeam 
is  then  latent  in  the  vegetable  structure.  The  sun  shin- 
ing on  a  meadow  causes  the  grass  to  grow.  If  the  hay 
made  from  it  be  eaten  by  an  animal,  the  same  amount  of 
force  will  be  liberated  as  was  received  from  the  sun.  A 
tree  towers  upward  through  a  century  of  sunshine.  When 
burned,  it  sets  free  as  much  force  as  was  needed  to  per- 
fect its  growth.  A  bushel  of  corn,  then,  represents  not 
alone  so  much  C,  H,  and  0,  but  also  an  amount  of  sun- 
force  which  is  available  for  any  purpose  to  which  we  wish 
to  apply  it.  (See  Conclusion.) 

Animals  Spend  Solar  Force. — In  the  process  of 
digestion  the  force  stored  in  the  plant  is  transferred  to 
the  animal,  is  given  out  by  its  muscles  on  their  oxi- 
dation and  produces  motion,  heat,  etc.  H3N,  C02,  and 
H20  are  decomposed  by  the  plant  and  organized  into 
complex  molecules  (see  p..  182),  full  of  potential  force. 
The  animal  oxidizes  the  organic  molecules,  and  breaks 
them  up  into  H3N,  C02,  and  H20  again — simple  mole- 
cules robbed  of  force  which  the  animal  has  used.  Thus 
the  plant  builds  up  and  the  animal  tears  down.  The 
plant  garners  in  the  sunbeam  and  the  animal  scatters  it 
again.  The  plant  reduces  and  the  animal  oxidizes. 

Uses  of  Watery  Vapor, — We  have  already  seen  the  uses 
of  H20.  As  vapor,  it  is  everywhere  present  and  ready  to 
supply  the  wants  of  animals  and  plants.  Were  the  air 
perfectly  dry,  our  flesh  would  become  shriveled  like  a 
mummy's,  and  leaves  would  wither  as  in  an  African 
simoom.  Kivers  and  streams  flow  to  the  ocean ;  yet  all 


THE     ATMOSPHERE.  101 


their  fountains  are  fed  by  the  currents  tlrat^movd-m  ttie 
air  above  us.  H20  rises  as  vapor,  flows  on  to  colder 
regions,  falls  as  rain,  dew,  snow,  or  hail,  and  then  work- 
ing as  it  goes  whatever  it  finds  to  do,  moistening  a  plant 
or  turning  a  water-wheel,  wends  its  way  back  to  the 
ocean.  Thus  Niagara  itself  must  first  rise  to  the  clouds 
as  vapor  before  it  can  fall  as  a  cataract. 

'Permanence  of  the  Atmosphere. — The  elements 
of  the  air  unite  to  form  HN03  only  by  the  passage  of  elec- 
tricity, and  then  in  minute  quantities.  If  they  combined 
more  readily  we  should  be  constantly  exposed  to  a  shower 
of  this  corrosive  acid  that  would  be  destructive  to  all 
vegetation,  clothing,  and  even  our  bodies  themselves. — 0 
and  N  have  never  been  solidified  or  liquefied  by  the  sever- 
est cold  or  pressure;  while  C02  is  reduced  from  its  gas- 
eous form  only  by  an  apparatus  specially  contrived  for 
the  purpose*  These  substances  are  therefore  constantly 
in  the  condition  to  promptly  supply  the  demands  of 
animals  and  plants. — Watery  vapor,  on  the  contrary,  is 
deposited  as  dew  or  rain  by  the  slightest  change  of  tem- 
perature ;  this  readiness  of  condensation  is  equally  neces- 
sary to  meet  the  wants  of  animal  and  vegetable  life. — 
The  permanence  of  the  air  produces  all  the  uniformity 
of  sound.  Were  the  proportions  of  the  atmosphere  to 
change,  all  "  familiar  voices  "  would  become  strange  and 
uncouth,  while  the  harmonies  of  music  would  shock 
us  with  unwonted  discord.*  Each  element  of  the  air  is 
adapted  to  a  special  work,  and  all  are  fitted  to  the  present 
order  of  nature. 


*  If,  by  some  means,  the  air  of  a  concert-room  could  be  changed  to  H,  for 
instance,  the  bass  voices  would  become  irresistibly  comic  and  shrill,  while  the 
tenor  would  emulate  railway  whistles. 


.102 


INORGANIC     CHEMISTRY. 


THE     HALOGENS. 


Chlorine..  Symbol,  Cl)  Atomic  Weight,  35,5)  Specific  Gravity,  2,43 
Iodine....      "        I)       "          "        127,)       "  4,94 

Bromine..      "     Brj       "          "          80.)       "     (at  32°),  3,18 


Fluorine.. 


Fj 


1,31 


These  four  elements  are  closely  allied,  and  form  a  class 
of  compounds  known  as  the  halogens,  from  hals,  salt,  be- 
cause they  resemble  common  salt  (Nad).* 

CHLORINE  is  named  from  its  green  color.  It  is  chiefly 
found  in  salt,  of  which  it  forms  60  per  cent.  It  is  pre- 

Fig.  A3. 


Preparing  01. 

*  In  comparing  the  halogens  with  one  another,  the  chemical  activity  of  F, 
which  has  the  smallest  atomic  weight,  is  the  most  powerful ;  next  in  the  order 
of  activity  is  Cl,  then  Br,  and,  lastly.  I,  the  atomic  weight  increasing  as  the  chem- 
ical energy  declines.  Cl  is  gaseous,  Br,  liquid,  and  I  solid.  The  specific  gravity, 
the  fusing  point,  and  the  boiling  point,  rise  as  the  atomic  weight  increases.  The 
halogens  combine  energetically  with  the  metals,  and,  when  united  with  the  same 
metal,  furnish  compounds  which  are  isomorphous  ;  that  is  to  say,  they  all  crys- 
tallize in  the  same  form— potassium  fluoride,  chloride,  bromide,  and  iodide,  for 
example,  all  crystallize  in  cubes.  Each,  also,  forms  with  H  a  soluble,  powerful 
acld-HCl,  HI,  HBr,  HF. 


THE     HALOGENS.  103 

pared  by  heating  NaCl  with  Mn02,  H2S04,  and  H20.* 
This  mixture  liberates  the  gas  in  great  quantities.  Cl  is 
heavier  than  common  air,  and  hence  may  be  collected  by 
displacement,  as  in  the  preparation  of  C02,  or  a  solution 
of  the  gas  may  be  obtained  by  using  the  apparatus  shown 
in  Fig.  43,  while  the  excess  is  gathered  in  a  receiver. 

Properties. — Cl  has  a  greenish-yellow  color,  and  a  pecu- 
liarly disagreeable  odor.    It  produces  a  suffocating  cough, 
which  can  be  relieved  by  breathing  ammonia  or  ether. 
Arsenic,  Dutch  gold-leaf,  phosphorus,  etc.,  com- 
bine with  it  so  rapidly  as  to  inflame.    Powdered 
antimony  slowly   dropped  into  it  produces  a 
shower  of  brilliant  sparks.     Cold  water  absorbs 
about  twice  its  volume  of  the  gas,  which,  in 
the  sunlight,  turns  to  hydrochloric  acid  (HC1). 
Cl  has  such  a  powerful  affinity  for  H,  that  it 
wrill  even  attract  it  out  of  a  moist  organic  body, 
and  form  HC1.    It  acts  thus  upon  turpentine,  Turpentine 
depositing  its  C  in  great  flakes  of  soot.    It  dis-      in  CL 
charges  the  color  of  indigo,  ink,  wine,  etc.,  almost  in- 
stantaneously.    It  has  no  effect  on  printers'  ink,  the  col- 
oring matter  of  which  contains  no  H.     (See  p.  222.) 

Uses. — Bleaching. — In  domestic  bleaching  the 
cloth  is  first  boiled  with  strong  soap,  to  dissolve  the 
grease  and  wax,  and  then  laid  upon  the  grass,  being  fre- 
quently wet  to  hasten  the  action  of  the  air  and  sun.  The 
dew  seems  to  have  a  peculiar  influence,  while  the  corro- 
sive ozone  of  the  atmosphere  doubtless  aids  in  the  pro- 
cess. The  H  of  the  coloring  matter  unites  with  the  0  of 


The  chemical  reaction  is  as  follows : 

nganese    Sodium    Sulphuric  Manga 
Hoxide       Chloride        Acid         Sulpl 

MnO,     +    SNaCl    +   3HaSO,  =  MnSO,     +    2HNaSO4     +   2HaO  +  Cla 


Manganese    Sodium    Sulphuric  Manganese  Hydrogen  Sodi-  Trrn*pr    rhlnrina 
Dioxide       Chloride        Acid         Sulphate       urn  Sulphate     Water    CWOr 


104  INORGANIC     CHEMISTRY. 

the  air  or  dew,  forming  H20,  and  destroying  the  coloring 
compound.* 

The  method  of  bleaching  on  a  large  scale  is  as  follows : 
The  cloth  is  well  washed,  and  boiled  in  water  with  strong 
alkalies,  to  remove  the  grease,  etc.;  next  it  is  passed 
through  a  solution  of  chloride  of  lime,  and  lastly  through 
diluted  H2S04.  In  this  step  the  acid  unites  with  the 
lime,  and  sets  free  the  Cl,  which  in  turn  combines  with 
the  H  of  the  coloring  matter,  forming  HC1,  and  thus 
bleaches  the  cloth.  "About  twenty-four  hours  are  re- 
quired for  this  process,  and  the  cost  is  not  quite  a  cent 
per  yard."  Paper-rags  are  bleached  in  the  same  way  in 
paper-mills,  f 

^Disinfectant.  —  Cl  is  a  powerful  disinfectant.  It 
breaks  up  the  offensive  substance  by  uniting  with  its  H, 
as  in  bleaching.  Other  disinfectants,  as  burnt  paper, 
sugar,  etc.,  only  disguise  the  ill  odor  by  substituting  a 
stronger  one.  In  the  sick-room  Cl  is  set  free  from  chlo- 
ride of  lime  (bleaching  powder)  by  exposing  it  to  the  air 
in  a  saucer  with  a  little  H20.  The  gas  soon  passes  off, 
though  the  process  may  be  hastened  by  adding  a  few 
drops  of  dilute  acid.  Chloride  of  lime  is,  therefore,  of 


*  This  was  essentially  the  process  long  pursued  in  Holland,  where  linens  were 
formerly  carried  for  bleaching;  hence  the  term  "Holland  linen,"  still  in  use. 
The  H2O  about  Haarlem  was  thought  to  have  peculiar  properties,  and  no  other 
could  compete  with  it.  Cloths  sent  there  were  kept  the  entire  summer,  and  were 
returned  in  the  fall.  Later  a  similar  plan  was  adopted  in  England.  But  the  vast 
extent  of  grass-land  required,  the  time  occupied,  and  the  temptation  to  theft, 
made  the  process  extremely  tedious  and  expensive.  The  statute  laws  of  that 
time  abound  in  penalties  for  cloth  stealing.  It  is  estimated  that  all  the  men, 
women,  and  children  in  the  world  could  not,  by  the  old  way,  bleach  all  the  cloth 
that  is  now  used. 

t  Stains  can  be  removed  from  uncol&red  cloth  by  u  Labarraque's  Solution,"  a 
compound  of  Cl,  which  can  be  obtained  of  any  druggist.  Place  the  cloth  in  this 
liquid,  and  if  the  stain  is  obstinate,  pour  on  a  little  boiling  HSO,  or  place  it  in 
the  sun  for  some  hours.  Then  rinse  thoroughly  in  cold  HaO,  and  dry. 


THE    HALOGENS. 


105 


Fig.  U5. 


great  service  for  disinfecting  all  places  exposed  to  any 
noxious  or  unpleasant  effluvia.  Hospitals  and  rooms  in 
which  persons  have  died  of  a  contagious  disease  are  puri- 
fied by  placing  in  them  pans  full  of  a  mixture  which  is 
disengaging  Cl  in  large  quantities. 

Compounds.— ITydrochtoric  Acid,  Muriatic 
Acid,  HC1.  — When  Cl  and  H 
are  mixed  in  the  dark  and  ex- 
posed to  the  direct  sunlight  they 
unite  with  an  explosion.  In  the 
arts  HC1  is  prepared  from  H2S04 
and  NaCl.  The  reaction  is  as 
follows:  NaCl  +  H2S04=HCl  + 
HNaS04. 

Properties. — It  is  an  irrespira- 
ble,  irritating,  acid  gas,  with  an 
intense  attraction  for  H20,  which 
causes  it  to  produce  white  fumes 
in  the  air.  Water  at  60°  will 
absorb  over  450  times  its  volume 
of  the  gas,  producing  the  liquid  known  as  "Muriatic 
Acid."  It  dissolves  the  metals,  and  forms  chlorides. 
When  pure  it  is  colorless,  but  has  ordinarily  a  yellow 
tinge,  due  to  various  impurities.  Its  tests  are  H3N,  with 
which  it  forms  a  white  cloud  of  sal-ammoniac  fumes, 
and  silver  nitrate,  from  which  it  precipitates  AgCl.  With 
HN03  it  makes  aqua-regia,*  or  royal  water,  so  called 
because  it  dissolves  Au,  the  "  king  of  the  metals ; "  Cl  is 
set  free,  which,  in  its  nascent  state,  attacks  the  Au  and 
combines  with  it. 


Preparing  HC1. 


*  Boil  HC1  in  a  test  tube  with  fragments  of  gold-leaf.  They  will  not  dissolve. 
Add  a  few  drops  of  HNO,,  and  a  yellow  solution  of  gold  chloride  will  be  quickly 
formed. 


106  IN  ORGANIC     CHEMISTRY. 

Calcium  IFypochlorite  (CaCl202)  is  an  ingredient 
of  chloride  of  lime  or  bleaching  powder.  This  is  prepared 
by  passing  a  current  of  Cl  over  pans  of  fresh  slacked 
lime.  It  is  much  used  in  bleaching  and  as  a  disin- 
fectant. 

Calcium  Chloride,  the  other  compound  of  bleach- 
ing powder,  was  made  in  preparing  C02  (see  p.  74).  It 
is  used  by  chemists  for  drying  gases.  It  absorbs  H20  so 
greedily  that  in  the  open  air  it  will  soon  dissolve. 

BROMINE — named  from  its  bad  odor — is  a  poisonous, 
volatile,  deep-red  liquid,  with  the  general  properties  of 
Cl.*  It  is  principally  found  in  sea- water,  forms  bromides 
with  the  metals,  and  is  used  in  photography  and  medicine. 

FLUORINE  is  the  only  element  that  will  not  unite  with 
0.  It  exists,  in  small  quantities,  in  the  enamel  of  the 
teeth.  It  is  found  in  Derbyshire  or  fluor  spar  (CaF2),  of 
which  beautiful  ornaments  are  made.  It  unites  with  H, 
forming  hydrofluoric  acid  (HF),  noted  for  its  corrosive 
action  on  glass. \  (See  Appendix?)  This  eats  out  the 
silica  or  sand  from  the  glass,  and  is  therefore  used  for 
etching  labels  on  glass  bottles  and  on  shop  windows. — 
Example :  Powdered  fluor  spar  is  placed  in  a  lead  tray, 
and  covered  with  dilute  H2S04.  The  heat  of  a  lamp  ap- 
plied beneath,  for  a  moment  only,  liberates  the  gas  in 
white  fumes  very  rapidly.  The  plate  of  glass  is  covered 
with  wax,  and  the  design  to  be  etched  is  traced  upon  it 
with  a  sharp-pointed  instrument.  This  is  then  laid  over 
the  tray,  and  the  escaping  gas  soon  etches  the  lines  laid 

*  Br  is  the  only  element,  except  Hg,  which  is  liquid  at  ordinary  temperatures, 
t  So  delicate  is  the  test  that  by  this  means  the  presence  of  F  has  been  de- 
tected in  fossil  teeth. 


THE     HALOGENS  107 

bare  into  an  appearance  like  ground  glass.  A  solution  of 
H  F  in  H  20  is  often  sold  for  this  purpose.  It  is  kept  in 
lead  or  gutta-percha  bottles,  combines  with  H20  with  a 
hissing  sound,  like  red-hot  iron,  and  must  be  handled 
with  care,  as  a  minute  drop  even  will  sometimes  produce 
an  ulcer. 

IODIDE  is  named  from  its  beautiful  violet-colored  vapor. 
It  is  made  from  kelp  (the  ashes  of  sea-weed),  and  is  found 
in  sea-water  and  in  some  mineral  springs.  It  crystal- 
lizes in  bluish-black  scales,  emits  a  smell  resembling  that 
of  Cl,  sublimes  *  slowly,  and  is  deposited  in  crystals  on 
the  sides  of  the  bottle  in  which  it  is  kept.  I  is  sparingly 
soluble  in  H20,  but  readily  in  ether  or  alcohol.  It  in- 
flames spontaneously  when  in  contact  with  phosphorus,  f 
Its  compounds  with  the  metals,  called  the  iodides,  are  re- 
markable for  their  variety  and  brilliancy  of  color.  (See 
Appendix.)  It  stains  cloth  a  yellowish  tint,  which  may 
be  removed  by  a  solution  of  potassium  iodide.  Its  test  is 
starch,  forming  the  blue  iodide  of  starch.  J  I  reveals  the 
presence  of  this  substance  in  potatoes,  apples,  etc.  §  It  is 
much  used  in  medicine  to  scatter  scrofulous  or  cutaneous 
eruptions  and  swellings. 


*  A  body  is  said  to  sublime  when  it  rises  as  vapor  and  condenses  in  the  solid 
form ;  when  it  condenses  as  a  liquid  it  is  said  to  distil. 

t  Place  on  a  clean,  white  dish  a  few  scales  of  iodine  and  a  bit  of  phosphorus  as 
large  as  a  pea.  They  will  soon  combine,  igniting  the  phosphorus  and  subliming 
a  part  of  the  iodine. 

$  Mix  one  or  two  drops  of  a  solution  of  potassium  iodide  with  a  little  dilute 
starch  mucilage  ;  no  change  of  color  will  occur.  Add  a  single  drop  of  Cl  water 
to  the  mixture  ;  an  immediate  coloration  will  occur,  owing  to  the  combination 
of  the  Cl  with  the  K,  while  I  is  set  free,  which  acts  upon  the  starch.  Add  a  little 
more  chlorine  water ;  the  color  disappears,  owing  to  the  formation  of  chlorine 
iodide,  which  is  without  action  on  starch. 

§  Pour  a  few  drops  of  a  solution  of  iodine  in  alcohol  on  a  freshly-cut  potato  or 
apple.  Blue  specks  will  show  the  presence  of  starch. 


108  INORGANIC     CHEMISTRY. 

BORON. 
Symbol,  B  ........  Atomic  Weight,  10,9, 

3$oron  is  found  in  nature  in  combination  with  0,  as 
boracic  acid.  Thm  is  abundant  in  the  volcanic  districts 
of  Tuscany.*  Along  the  sides  of  the  mountains,  series 


Fig. 


Preparing  Boracic  Acid. 

of  basins  are  excavated  and  filled  with  cold  water  from 
the  neighboring  springs.  Into  these  basins  the  jets  of 
steam,  charged  with  boracic  acid,  are  conducted.  The 
H20  absorbs  the  acid,  and  becomes  itself  heated  to  the 
boiling-point.  It  is  then  drawn  off  into  the  next  lower 
basin.  This  process  is  continued  until  the  bottom  one  is 
reached,  when  the  (solution  runs  into  leaden  pans  heated 
by  the  steam  from  the  earth-;  here  the  H20  is  evaporated, 
and  the  boracic  acid  collected. 

*  Throughout  an  area  of  nearly  thirty  miles,  is  a  wild,  mountainous  region,  of 
terrible  violence  and  confiwion.  The  surface  is  ragged  and  blasted.  Everywhere 
there  issue  from  the  ground  jets  of  steam,  filling  the  air  with  most  offensive 
odors.  The  earth  itself  shakes  beneath  the  feet,  and  frequently  yields  to  the 
tread,  engulfing  man  anfl  Deast.  "  The  waters  below  are  heard  boiling  with 
strange  noises,  and  are  seen  breaking  out  upon  the  surface.  Of  old,  it  was  re- 
garded as  the  entrance  to  Uell.  The  peasants  pass  by  in  terror,  counting  their 
beads  and  imploring  the  protection  of  the  Virgin." 


SILICON.  109 

2tora%  (Na20,  2B203, 10H20)  is  a  salt  of  this  acid. 
It  is  a  natural  production,  obtained  by  the  drying  of  cer- 
tain lakes  in  Thibet,  and  lately  found  in  California. 
When  dissolved  in  alcohol  it  gives  a  peculiar  green  tint 
to  the  flame.  This  is  an  easy  test  of  the  presence  of  this 
acid.  Borax  is  employed  in  welding.  It  dissolves  the 
oxide  of  the  metal,  and  keeps  the  surface  bright  for  sol- 
dering. It  softens  hard  water  by  uniting  with  the  soluble 
salts  of  lime  or  magnesia,  and  making  insoluble  ones 
which  settle  and  form  a  thin  sediment  in  the  bottom  of 
pitchers  in  which  it  is  placed.* 


SILICON. 

Symbol,  Si Atomic  Weight,  28 Specific  Gravity,  2,49, 

Sources. — Silicon  is  found  in  combination  with  0  as 
silica  (silicic  anhydride,  Si02),  commonly  called  silex  or 
quartz.  So  abundant  is  this  oxide  that  it  probably  com- 
prises nearly  one-half  of  the  earth's  crust.  (See  Geology, 
p.  40.)  It  forms  beautiful  crystals  and  some  of  the  most 
precious  gems.  "When  pure,  it  is  transparent  and  colorless, 
as  in  rock  crystal.  Jasper,  amethyst,  agate,  chalcedony, 
blood-stone,  chrysoprase,  sardonyx,  etc.,  are  all  common 
flint-stone  or  quartz,  colored  with  some  metallic  oxide. 
The  opal  is  only  Si 02  and  H  20.  Sand  is  mainly  fine  quartz, 
which,  when  hardened  and  cemented,  we  call  sandstone. 
Yellow  or  red  sand  is  colored  by  iron-rust. 

Properties. — It  is  tasteless,  odorless,  and  colorless.    It 

*  Borax  is  also  extensively  used  in  "  blow-pipe  analysis."  When  it  is  melted 
with  chromium  oxide,  it  gives  an  emerald  green ;  with  cobalt  oxide,  a  deep  blue ; 
with  copper  oxide,  a  pale  green ;  with  manganese  oxide,  a  violet. 


110  I  NO  R  G  A  NI C     C  HE  MIS  TRY. 

seems  very  strange  to  call  such  an  inert  substance 
an  anhydride ;  yet  it  readily  unites  with  the  alkalies, 
neutralizes  their  properties,  and  forms  a  large  class  of 
salts  known  as  the  silicates,  which  are  found  in  the  most 
common  rocks, — Example  :  feldspar,  found  in  granite. 

Silica  in  Soil  and  Tlants.—  Silica  is  insoluble 
in  H20,  unless  it  contains  some  alkali.  When  the  sili- 
cates, so  abundant  in  rocks,  disintegrate  and  form  soil,  the 
alkali  and  silica  are  both  dissolved  in  the  water,  and  taken 
up  by  the  roots  of  plants.  We  see  the  silex  on  the  surface 
of  scouring-rushes  and  sword-grass,  which  cut  the  fingers 
if  handled  carelessly.  It  gives  stiffness  to  the  stalks  of 
wheat  and  other  grains,  and  produces  the  hard,  shiny 
surface  of  bamboo,  corn,  etc. 

^Petrifaction .  —  Certain  springs  contain  large  quan- 
tities of  some  alkaline  carbonate ;  their  waters,  therefore, 
dissolve  silica  abundantly.  If  we  place  a  bit  of  wood  in 
them,  as  fast  as  it  decays,  particles  of  silica  will  take  its 
place — atom  by  atom — and  thus  petrify  the  wood.  The 
wood  has  not  been  changed  to  stone,  but  has  been  replaced 
ly  stone. 

Compounds. — The  Silicates.  —  Glass*  is  a  mixture 


*  Glass  was  known  to  the  ancients.  Hieroglyphics,  that  are  as  old  as  the 
sojourn  of  the  Israelites  in  Egypt,  represent  glass-blowers  at  work,  much  after 
the  fashion  of  the  present.  In  the  ruins  of  Nineveh,  articles  of  glass,  such  as 
vases,  lenses,  etc.,  have  been  discovered.  Mummies,  three  thousand  years  old, 
are  adorned  with  glass  beads.  The  inventor  is  not  known.  Pliny  tells  us  that 
some  merchants,  once  encamping  on  the  sea-shore,  found  in  the  remains  of  their 
fire  bits  of  glass,  formed  from  the  sand  and  ashes  of  the  sea-weed  by  the  heat ; 
but  this  is  impossible,  as  an  open  fire  could  not  be  sufficient  to  melt  these 
materials.  In  the  fourth  century,  the  glass-works  at  Alexandria  produced  most 
exquisite  ornaments,  with  raised  figures  beautifully  cut  and  gilded.  As  late, 
however,  as  the  twelfth  century,  a  house  with  glass  windows  was  esteemed 
something  magnificent ;  and  we  read  that,  during  Queen  Elizabeth's  reign,  when 
the  Duke  of  Northumberland  came  to  town  to  pass  the  winter,  the  windows  of 
his  castle  were  taken  out  and  packed  away  for  safe-keeping  until  spring. 


SILICON.  Ill 

of  several  silicates.  There  are  four  varieties  used  in  the 
arts.  1.  Window  or  plate  glass  is  composed  of  silicates  of 
calcium  and  sodium.  It  is  made  by  heating  white  sand, 
sal-soda,  and  lime  in  clay  crucibles  for  about  forty-eight 
hours,  when  the  materials  fuse  and  combine  into  a  double 
silicate.  The  Ca  hardens  and  gives  lustre ;  the  N  a  ren- 
ders the  glass  fusible,  but  imparts  a  green  tint.  2.  Bohe- 
mian glass  consists  of  silicates  of  calcium  and  potassium. 
Unlike  Na,  K  gives  no  color.  3.  Flint-glass*  or  crystal 
contains  silicates  of  potassium  and  lead.  The  latter  is 
used  in  large  quantities  and  produces  a  soft,  lustrous 
glass,  which  can  be  ground  into  imitation  gems,  table- 
ware, chandelier  pendants,  prisms,  etc.  4.  Green  bottle- 
glass  is  made  of  silicates  of  calcium,  sodium,  aluminum, 
and  iron.  The  last  gives  the  opaque  green  of  the  com- 
mon junk  bottle. 

Coloring  Glass. — A  small  quantity  of  some  metallic 
oxide  melted  with  the  glass  furnishes  any  tint  desired : 
Co  gives  a  beautiful  sapphire  blue ;  Au  or  Cu,  a  ruby-red ; 
Mg,  a  violet;  U,  a  yellow;  As,  a  soft  white  enamel,  as  in 
lamp-shades ;  and  Sn,  a  hard  enamel,  as  in  watch-faces. 

Annealing  Glass.  —  If  the  glass  utensils  were 
used  immediately,  they  would  be  found  extremely  brittle, 
and  would  drop  in  pieces  in  the  most  unaccountable  way. 
The  heat  of  the  hand  or  a  draft  of  cool  air  would  some- 
times crack  off  the  thick  bottom  of  a  tumbler.  They  are 
therefore  cooled  very  gradually  for  days,  which  allows 
the  particles  to  assume  their  natural  place,  and  the  mo- 
lecular attractions  to  become  equalized.f 

*  So  called  because  •oulverized  flint  was  formerly  used  for  sand. 
t  This  principle  is  "beautifully  illustrated  by  the  philosophical  toy  known  as 
the  "  Prince  Rupe*v*»  jn-op.-"    (See  Philosophy,  page  40.) 


112  INORGANIC     CHEMISTRY. 

Ornamental  If  are. — Venetian  balls  or  paper 
weights  are  made  by  arranging  bits  of  colored  glass  in 
the  form  of  fruits,  flowers,  etc.,  and  then,  inserting  them 
in  a  hollow  globe  of  transparent  glass,  still  hot,  the  work- 
man draws  in  his  breath,  and  the  pressure  of  the  air 
above  collapses  the  globe  upon  the  colored  glass,  and 
leaves  a  concave  surface  in  the  opposite  side  of  the  weight. 
The  lens  form  always  magnifies  the  size  of  the  figures 
within. 

Fubes  and  tBeads. — In  making  glass  tubing,  the 
workman  inserts  his  iron  blowing-tube  in  a  pot  of  melted 
glass,  and  gathers  upon  the  end  a  suitable  amount; 
drawing  this  out,  he  blows  into  the  tube,  swelling  the 
glass  into  a  globular  form.  Another  dip  into  the  pot  and 
another  blow  increase  its  size,  until  at  last  a  second 
workman  attaches  an  iron  rod  to  the  other  end.  The 
two  men  then  separate  at  a  rapid  pace.  The  soft  glass 
globe  diminishes  in  size  as  it  lengthens,  until  at  last  it 
hangs  between  them  a  glass  tube  of  a  hundred  feet  in 
length,  and  perhaps  only  a  quarter  of  an  inch  in  diameter. 

Tor  making  beads,  glass  tubes  are  cut  in  short  pieces, 
and  then  worked  about  in  a  mixture  of  wet  ashes  and 
sand,  until  they  are  filled.  They  are  next  put  with  loose 
sand  in  a  cylinder  rapidly  revolving  over  a  hot  furnace. 
The  heat  softens  the  glass,  but  the  mixture  within  presses 
out  the  sides,  and  the  sand  grinds  the  edges,  until  at  last 
the  beads  become  round  and  perfect,  and  are  taken  out 
ready  for  market. 


SULPHUR.  113 

SULPHUR. 

Symbol,  S Atomic  Weight,  32 Specific  Gravity,  2, 

Sources. — S  is  found  native  in  volcanic  regions.  It  is 
mined  at  Mount  ^3Etna  in  great  quantities.  United 
with  the  metals  it  forms  sulphides,  known  as  cinnabar, 
iron  pyrites,  galena,  blende,  etc.  Combined  with  0  it 
exists  in  gypsum  (plaster),  heavy  spar,  and  other  sul- 
phates. It  is  found  in  the  hair,  and  many  dyes  contain 
Pb  which  unites  with  the  S,  and  forms  a  black  compound 
that  stains  the  hair.  It  is  contained  in  eggs,  and  so  tar- 
nishes our  spoons  by  forming  a  sulphide  of  silver.  It  is 
always  present  in  the  flesh,  and  hence  manifests  itself  in 
our  perspiration.  In  commerce  it  is  sold  as  brimstone, 
formed  by  melting  5  and  running  it  into  moulds ;  also 
as  flowers  of  sulphur,  obtained  by  sublimation. 

Properties. — It  is  insoluble  in  H20,  and  hence  taste- 
less. Its  solvents  are  carbon  disulphide  (CS2),  oil  of  tur- 
pentine, and  benzole.  It  is  a  non-conductor  of  heat,  and 
crackles  when  we  grasp  it  with  a  warm  hand.  It  mani- 
fests itself  under  four  allotropic  forms:  1st,  octahedral 
crystals ;  2d,  prismatic  crystals ;  3d,  an  amorphous  (with- 
out form)  or  uncrystallized  state;  and  4th,  a  viscid 
condition.  The  last  is  the  most  interesting. — Example : 
When  S  is  melted,  and  then  heated  more  strongly,  it 
changes  to  a  thick,  viscid,  dark-colored  liquid  resembling 
molasses.  If  this  is  poured  into  cold  water,  it  becomes 
elastic  like  india-rubber.  In  this  form  it  is  used  for  tak- 
ing impressions  of  medals,  coins,  etc.  (See  Appendix.) 


lllf  INORGANIC     CHEMISTRY. 

Uses.— On  account  of  its  ready  inflammability,  S  is 
employed  in  the  making  of  matches  and  gunpowder,  but 
its  chief  consumption  is  in  the  production  of  H2S04. 

Compounds.— Su2p?iurous  An?iydride,  S02,  an 
irrespirable,  suffocating  gas,  is  formed  by  S  burning  in  the 
air,  as  in  the  lighting  of  a  match.  It  is  very  poisonous, 
and  extinguishes  combustion.  If  our  "  chimney  burns  " 
at  any  time,  we  can  easily  quench  the  flame  by  pouring  a 
little  S  into  the  stove. 

Uses. — SO 2  is  used  for  bleaching  silk,  straw,  and 
woollen  fabrics.  Cl  turns  them  yellow,  but  S02  unites 
with  the  coloring  matter,  and  forms  a  colorless  compound. 
Its  action  is  therefore  very  different  from  that  of  Cl. — 
Example :  A  red  rose,  bleached  in  the  fumes  of  burning 
S,  can  be  restored  to  its  original  color  by  very  dilute 
H2S04.  This  acid  being  stronger,  neutralizes  the  action 
of  the  SO 2.  New  flannels,  washed  in  strong  soap,  turn 
yellow,  because  the  alkali  of  the  soap*unites  with  the  S02 
used  in  bleaching  the  cloth,  and  thus  sets  free  the  origi- 
nal color.  S  is  also  frequently  employed  to  check  fer- 
mentation, as  when  it  is  burned  in  a  barrel  before  filling 
with  new  cider. 

Sulphuric  Anhydride,  S03,  may  be  prepared  by 
the  oxidation  of  S02  or  by  removing  H20  from  H2S04. 
It  is  often  called  anhydrous  sulphuric  acid.  If  Nord- 
hausen  acid  *  be  heated,  the  vapors  may  be  condensed  in 
a  mass  of  silky,  crystalline  fibres  of  S03.  This  will  show 
no  acid  reaction,  will  not  redden  blue  litmus-paper,  and, 
if  the  fingers  are  dry,  can  be  molded  like  wax.  If  it  be 
dropped  into  H20,  it  will  hiss  like  a  red-hot  iron,  and 

*  So  named  from  the  German  town  near  which  it  was  formerly  made  by  the 
distillation  of  green  vitriol  (iron  sulphate). 


SULPHUR.  115 

forming  H2S04,  will  exhibit  all  the  properties  of  that 
corrosive  substance. 

SulpJmric  Acid,  Oil  of  Vitriol,  is  the  king  of  the 
acids.  It  is  of  the  utmost  importance  to  the  manufac- 
turer and  chemist,  as  it  is  used  in  the  preparation  of 
nearly  all  other  acids,  and  forms  many  valuable  com- 
pounds. 

Preparation. — If  we  burn  a  little  S  in  a  hot- 
tie  it  will  soon  become  filled  with  a  white 
cloud  of  SO  2-    Now  another  atom  of  0  would 
make  this  S03,  sulphuric  anhydride.     Nitric 
acid,  it  will  be  remembered,  easily  parts  with 
its  0.     So  if  we  stir  the  S02  with  a  swab  wet 
in  aqua-fortis,  we  shall  quickly  see  the  familiar 
hyponitric  acid  fumes,  indicating  that  the  acid 
has  been  decomposed  and  has  given  up  its  0. 
Add  a  little  water  and  shake  the  jar  thoroughly.     On 
testing  the  liquid  with  a  few  drops   of  a  solution   of 
barium   chloride,   the    beautiful   white    precipitate   will 
prove  the  presence  of  H2S04..* 

2'?ie  Manufacture  of  Sulphuric  Acid  on  a 
large  scale  is  based  on  the  principle  of  the  preceding 
illustration.  The  process  is  facilitated  by  the  curious 
fact  that  the  nitric  oxide  (NO)  produced  by  the  decom- 
position of  the  HN03  has  the  property  of  acting  as  a  car- 
rier of  0  between  the  common  air  and  S02,  whereby  it 
can  oxidize  an  almost  indefinite  quantity,  thus  forming 
S03,  which,  in  the  presence  of  H  20,  will  be  at  once  con- 
verted into  H2S04.  S  is  burned  in  a  current  of  air  in  fur- 
naces A,  A.  In  the  stream  of  heated  gas  is  suspended  an 

*  The  reaction  in  making  the  acid  maybe  thus  expressed:  2HNO3  +  SOa« 
HaSOt+2NOa. 


ne 


INORGANIC     CHEMISTRY. 


iron  pot,  £,  charged  with  a  mixture  of  sodium  nitrate  and 
H2S04.  Vapors  of  HN03are  thus  set  free,  and  these 
pass  on  mixed  with  S02  and  excess  of  atmospheric  air. 


Fig.  It8. 


Manufacture  of  Ha  SO  4 . 

The  mingled  gases  pass  into  immense  chambers,  F,  of 
sheet  lead.  A  shallow  layer  of  H20,  d,  covers  the  floor, 
and  the  intermixture  and  chemical  action  of  the  gases 
are  further  favored  by  the  injection  of  jets  of  steam,  e, 
supplied  from  the  boiler,  G-. 

The  chemical  action  which  ensues  may  be  explained 
as  follows : — The  nitric  acid  is  quickly  reduced  to  nitric 
oxide,  NO.  This  takes  up  an  atom  of  0  from  the  air, 
becoming  N02,  and  flies  back  to  the  S02  making  a  mole- 
cule of  SO 3,  which,  with  a  molecule  of  H20  becomes 
H2S04,  a  molecule  of  sulphuric  acid.  The  NO  once 
more  seeks  the  air  and  returns  laden  with  0  for  the  S02. 
This  process  continues  until  the  chamber  becomes  so  full 


SULPHUR.  117 

of  the  sluggish  N  that  the  other  gases  are  nearly  lost  in 
it,  when  they  are  allowed  to  escape  gradually.  The  weak 
sulphuric  acid  which  collects  on  the  floor  is  drawn  off 
and  condensed  by  evaporation  in  lead  pans,  and  finally, 
when  it  begins  to  corrode  the  lead,  in  platinum  or  glass 
stills.  It  is  lastly  put  in  large  bottles  packed  in  boxes 
called  carboys,  when  it  is  ready  for  transportation. 

Properties. — It  is  a  dense,  oily  liquid,  without  odor, 
and  of  a  brownish  color.  Its  affinity  for  moisture  is  most 
remarkable.  If  exposed  in  an  open  bottle  it  gradually 
absorbs  water  from  the  air,  and  increases  in  bulk, 
sometimes  even  doubling  its  weight.  It  blackens  wood 
and  other  organic  substances,  by  taking  away  their  H20 
and  leaving  the  C.*  When  mixed  with  H20,  it  occupies 
less  space  than  before,  and  produces  much  heat;  4  parts 
of  acid  to  1  of  H20  will  boil  a  test-tube  of  water.  It 
commonly  contains  lead,  which  falls  as  a  milky  precipi- 
tate (PbSO^.)  when  the  acid  is  diluted.  It  is  the  strongest 
of  the  acids,  and  will  displace  the  others  from  their  com- 
pounds. It  stains  cloth  red,  but  the  color  can  be  re- 
stored by  an  alkali,  if  applied  immediately.  Its  test  is 
barium  chloride,  which  forms  a  white,  cloudy  precipi- 
tate. In  this  way  a  drop  of  H2S04  can  be  detected  in  a 
quart  of  H20. 

Jlydrogen  Sulphide,  H2S,  Sulphur  eited  Hydrogen, 
Sulphydric  Acid. — This  gas  is  produced  in  the  decay  of 
organic  matter,  and  is  always  found  near  cess-pools,  drains, 
and  sinks,  turning  lead  paint  black  and  emitting  a  dis- 
agreeable smell.  It  gives  the  characteristic  odor  to  the 

*  Strong  oil  of  vitriol  poured  on  a  little  loaf-sugar  moistened  with  hot  water, 
will  cause  an  energetic  boiling  and  a  copious  formation  of  black  charcoal.  Sugar 
consists  of  water  and  charcoal,  and  gives  up  the  former  to  satisfy  the  acid. 


118 


INORGANIC    CHEMISTRY. 


H2s. 


mineral  waters  of  Avon, 
Clifton,  Sharon,  and 
other  celebrated  sulphur 
springs.  It  is  prepared 
by  the  action  of  dilute 
H2S04  upon  ferrous  sul- 
phide (FeS).  The  reac- 
tion is  as  follows:  FeS-f 
H2S04=FeS04+H2S. 

H2S  has  the  disgusting 
odor  of  rotten  eggs.  It  is 
very  poisonous,  and  there- 
fore makes  an  open  sewer 

destructive  to  health.  Its  solution  in  H20  is  much  used 
in  the  laboratory  to  precipitate  many  of  the  metals  as 
sulphides.  Its  test  is  lead  acetate  (sugar  of  lead.) 

Carbon  1)isu2p?iide  ,  CS2,  is  produced  by  passing 
the  vapor  of  S  over  red-hot  coals.  It  is  a  volatile,  color- 
less liquid,  and  has  never  been  frozen.  The  fact  that 
a  yellow,  odorless  solid  thus  unites  with  a  black,  odorles? 
solid  to  form  such  a  colorless,  odoriferous  liquid,  illus- 
trates very  finely  the  power  of  chemical  affinity.  CS2 
readily  dissolves  S,  P,  and  I.  It  is  a  powerful  refractor 
of  light,  and  is  used  for  filling  hollow,  glass  prisms 
employed  in  experiments  with  the  solar  spectrum.  In 
its  combustion  it  unites  with  0,  forming  C02  and  S02. 


PRACTICAL     QUESTIONS. 

1.  If  chlorine  water  stands  in  the  sunlight  for  a  time,  it  will  only 
redden  a  litmus-solution.     Why  does  it  not  bleach  it  ? 

2.  Why  do  tinsmiths  moisten  with  HC1,  or  sal-ammoniac,  the 
surface  of  metals  to  be  soldered  ? 


PHOSPHORUS.  119 

3.  How  mucli  H  Cl  can  be  made  from  25  Ibs.  of  common  salt  ? 

4.  What  weight  of  NaCl  would  be  required  to  form  25  Ibs.  of 
muriatic  acid  ? 

5.  HC1  of  a  specific  gravity  of  1.2  contains  about  40  per  cent,  of 
the  gas.     This  is  very  strong  commercial  acid.    What  weight  could 
be  formed  by  the  HC1  acid  gas  produced  in  the  reaction  named  in 
the  preceding  problem  ? 

6.  What  is  the  difference  between  sublimation  and  distillation  ? 

7.  Why  do  eggs  discolor  silver  spoons  ? 

8.  Explain  the  principle  of  hair-dyes. 

9.  Why  is  new  flannel  apt  to  turn  yellow  when  -washed  ? 

10.  Is  it  safe  to  mix  oil  of  vitriol  and  water  in  a  glass  bottle  ? 

11.  What  is  the  color  of  a  sulphuric  acid  stain  on  cloth?    How 
would  you  remove  it  ? 

12.  What  causes  the  milky  look  when  oil  of  vitriol  and  water  are 
mixed  ? 

13.  What  is  the  chemical  relation  between  animals  and  plants  ? 
Which  perform  the  office  of  reduction,  and  which  of  oxidation  ? 

14.  How  many  pounds  of  S  are  contained  in  a  cwt.  of  H2S04  ? 

15.  How  much  0  and  H20  are  needed  to  change  a  ton  of  S02  to 
H2S04? 

16.  How  much  0  in  a  Ib.  of  H2S04  ? 

17.  State  the  analogy  between  the  compounds  of  0  and  S. 


PHOSPHORUS. 

Symbol,  P Atomic  Weight,  31 Specific  Gravity,  1,83, 

THE  name  Phosphorus  signifies  Ught-foarer,  given  be- 
cause this  substance  glows  in  the  dark.  It  was  called  by 
the  old  alchemists  "  the  son  of  Satan."  * 


*  The  following  singular  event  is  said  to  have  occurred  many  years  before  the 
reputed  discovery  of  phosphorus  by  Brandt  in  1669.  A  certain  Prince  San  Severe, 
at  Naples,  exposed  some  human  skulls  to  the  action  of  several  reagents,  and 
then  to  the  heat  of  a  furnace.  From  the  product  he  obtained  a  substance  which 
burned  for  months  without  apparent  loss  of  weight.  San  Severo  refused  to 


120 


INORGANIC     CHEMISTRY. 


Fig.  50. 


Manufacture  of  Phosphorus. 


Sources. — It  exists  in  small  quantities  in  rocks,  and  by 
their  decay  passes  into  the  soil,  is  taken  up  by  plants,  is 
then  stored  in  their  seeds  (wheat,  corn,  oats,  etc.),  and 
finally  passes  into  our  bodies.  As  calcium  phosphate 

("phosphate  of  lime"),  it  is  a 
prominent  constituent  of  our 
bones.*  Phosphorus  is  so  neces- 
sary to  the  operation  of  the  brain 
that  the  alchemists  had  a  saying, 
"  No  phosphorus,  no  brains." 

Preparation. — It  is  prepared 
in  immense  quantities  from 
bones.  These  are  first  calcined 
to  whiteness  to  burn  out  the 
animal  matter,  then  treated  with 
H2S04.  to  remove  the  Ca  (pp.  140,  230),  and  lastly  heated 
to  a  high  temperature  with  C  to  deoxidize  the  phospho- 
rus, which  distils  as  a  vapor,  and  is  condensed  under  H20. 
Properties. — It  is  a  waxy,  translucent  solid,  at  all  tem- 
peratures above  32°  emits  a  feeble  light,  melts  at  111°, 
and  ignites  at  a  little  higher  temperature.  It  should 
be  handled  with  the  utmost  care,  always  kept  and  cut 
under  H20,  and  never  used  except  in  very  small  quanti- 
ties. Its  burns  are  deep  and  dangerous.  It  is  poisonous, 
and  its  vapor  produces  horrible  ulcerations  of  the  jaw- 
bone in  workmen  who  use  it. 
Amorphous  Form. — Heated  for  several  hours  at 

divulge  the  process,  as  he  wished  his  family  vault  to  be  the  only  one  to  possess 
a  "perpetual  lamp"  the  secret  of  which  he  considered  himself  to  have  dis- 
covered. 

*  "  Of  phosphorus  every  adult  person  carries  enough  (If  Ibs.)  about  with  him 
in  his  body  to  make  at  least  4,000  of  the  ordinary  two-cent  packages  of  friction 
matches,  but  he  does  not  have  quite  sulphur  enough  to  complete  that  quantity  of 
the  little  incendiary  combustibles."— NICHOLS'S  Fireside  Science. 


PHOSPHORUS.  121 

a  temperature  of  about  500°,  in  a  close  vessel  filled 
with  N  or  C02,  the  melted  phosphorus  changes  into  a 
brick-red  solid,  and  seems  to  lose  all  its  former  proper- 
.ties.  It  is  now  insoluble  in  CS2,  which  can  be  used  to 
dissolve  out  every  trace  of  the  common  form.  Its  spe- 
cific gravity  is  increased  to  2.14  It  can  be  handled  with 
impunity,  carried  in  the  pocket  like  so  much  snuff,  and 
even  heated  to  nearly  400°  without  taking  fire.  At  a 
little  over  500°,  however,  it  changes  into  the  common 
form  and  bursts  into  a  blaze. 

Uses. — Matches. — The  principal  use  of  phosphorus  is 
in  the  manufacture  of  matches.  1.  The  Lucifer  Match. — 
The  bits  of  wood  are  first  dipped  in  melted  S  and  dried ; 
then  in  a  paste  of  phosphorus,  nitre,  and  glue,  which 
completes  the  process.  The  object  of  the  nitre  is  to  fur- 
nish 0  to  quicken  the  combustion.  Instead  of  this,  potas- 
sium chlorate  is  sometimes  used ;  it  can  be  recognized  by 
a  crackling  sound  and  jets  of  flame  when  ignited.  The 
tips  are  colored  by  red-lead,  or  Prussian  blue,  mixed  in 
the  paste.  When  a  match  is  burned,  the  reaction  is  as 
follows :  first,  the  friction  ignites  the  phosphorus,  which 
burns,  forming  P205 ;  *  this  produces  heat  enough  to  in- 
flame the  S,  which  makes  S02 ;  lastly,  the  wood  takes 
fire,  and  forms  C02  and  H20.  Thus  there  are  four  com- 
pounds produced  in  the  burning  of  a  single  match. 

2.  The  Safety  Match. — The  pieces  of  wood  are  dipped 
into  melted  paraffine  (see  p.  205)  and  dried.  They  are 


*  The  burning  phosphorus  produces  a  very  luminous  flame,  because  of  the 
reflection  of  light  from  the  dense  vapor  (P2OS).  The  following  experiment  is 
very  suggestive  in  this  connection  :  Ignite  a  bit  of  phosphorus  placed  upon  a 
sheet  of  white  paper.  The  paper  will  be  blackened  just  where  the  phosphorus 
lay,  but  will  not  take  fire;  and  after  the  flame  is  extinguished,  one  can  write 
upon  it  with  pen  and  ink,  close  to  the  edge  of  the  charred  portion. 

6 


INORGANIC     CHEMISTRY. 

then  capped  with  a  paste  of  potassium  chlorate,  sulphide 
of  antimony,  powdered  glass,  and  gum-water.  They 
ignite  only  when  rubbed  on  a  surface  covered  with  a 
mixture  of  red  phosphorus  and  powdered  glass. 

"Phosphorescence.  —  The  luminous  appearance  of 
putrefying  fish  and  decayed  wood  is  well  known.  The 
latter  is  sometimes  called  "  fox-fire."  The  "  glow-worm's 
fitful  light "  is  associated  with  our  memory  of  beautiful 
summer  evenings.  In  the  West  Indies,  fire-flies  are  found 
that  emit  a  green  light  when  resting,  and  a  red  one  when 
flying.  They  are  so  brilliant  that  one  will  furnish  light 
enough  for  reading.  The  natives  wear  them  for  orna- 
ments on  their  bonnets,  and  illuminate  their  houses  by 
suspending  them  as  lamps. — The  ocean  occasionally  takes 
on  strange  colors,  and  the  sailor  finds  his  vessel  plowing 
at  one  time  apparently  a  furrow  of  fire,  and  at  another 
one  of  liquid  gold.  The  water  is  all  aglow,  and  the  flames 
seem  to  leap  and  dance  with  the  waves  or  the  motion  of 
the  ship.  The  phenomenon  is  produced  by  multitudes 
of  animalcules  which  frequent  certain  seas.  Phosphores- 
cence is  generally  attributed  to  the  gradual  oxidation  of 
the  phosphorus  secreted  by  the  animal  or  plant. 

Compounds.— Jlydrogen  ^Phosphide,  H3P,  Phos- 
phuretted  Hydrogen,  is  formed  in  the  decomposition  of 
bones  and  organic  substances.  It  is  a  poisonous  gas, 
remarkable  -for  its  disgusting  odor,  for  igniting  spontane- 
ously on  coming  to  the  air,  and  for  the  singular  beauty  of 
the  rings  formed  by  its  smoke.  It  is  prepared  by  heat- 
ing in  a  retort  a  strong  solution  of  potash  containing  a 
few  bits  of  phosphorus.  It  has  been  thought  by  some 
that  the  Will-o'-the-wisp,  Jack-o'-the-lantern,  etc.,  as  seen 
near  graveyards  and  in  swampy  places,  are  produced  by 


123 


Preparation  of  H3P. 

this  gas  coming  off  from  decaying  substances,  and  igniting 
as  it  reaches  the  air. 


ARSENIC. 


Symbol,  As. . .  .Atomic  Weight,  75 Specific  Gravity,  5,9, 

Volatilizes  without  fusion  at  about  356°  F. 

As  is  a  brittle,  steel-gray  metal,*  commonly  sold,  when 
impure,  as  cobalt. \  If  heated  in  the  open  air  it  gives  off 
the  odor  of  garlic,  which  is  a  test  of  As. 

*  Arsenic  very  much  resembles  phosphorus  in  its  general  properties,*and  is 
therefore  classified  with  it,  hut  it  conducts  electricity  moderately,  and  has  a  high 
brilliancy.  It  seems  to  be  intermediate  between  the  non-metals  and  the  metals. 

t  Cobalt  is  a  reddish- white  metal,  found  in  combination  with  arsenic.  Co 
received  its  name  from  the  miners,  because  its  ore  looked  so  bright  that  they 
thought  they  would  obtain  something  valuable ;  but  when,  by  roasting,  it  crum- 
bled to  ashes,  they  believed  themselves  mocked  by  the  evil  spirit  (Kobolt)  of  the 
mines.  The  oxide  of  cobalt  makes  a  beautiful  blue  glass,  which,  when  ground 
fine,  is  called  smalt.  It  is  used  for  tinting  paper,  and  by  laundry  women  to  give 
the  finished  look  to  cambrics,  linen,  etc.  Its  impure  oxide,  called  zaffer,  imparts 
the  blue  color  to  common  earthenware  and  porcelain.  The  chloride(CoCla)is  used 
as  a  sympathetic  ink.  Letters  written  with  a  dilute  solution  of  it  are  invisible 
when  moist  with  the  H2O  absorbed  from  the  air,  but  on  being  dried  at  the 
stove,  again  become  blue.  If  the  paper  be  laid  aside  the  writing  will  disap- 
pear, but  may  be  revived  in  the  same  manner.  A  winter  landscape  may  be 
drawn  with  India-ink,  the  leaves  being  added  with  this  ink.  On  being  brought 
to  the  fire  it  will  bloom  into  the  foliage  of  summer. 


124  INORGANIC     CHEMISTRY. 

Arsenious  Anhydride,  As203. — This  is  the  well- 
known  " ratsbane"  and  is  sometimes  sold  as  simply 
"  arsenic." 

Preparation. — It  is  made  in  Silesia,  by  roasting  arseni- 
cal iron-ore  at  the  bottom  of  a  tower,  above  which  is  a 
series  of  rooms  through  which  the  vapors  ascend,  and 
pass  out  at  a  chimney  in  the  top.  The  As  burns,  form- 
ing As203,  which  collects  as  a  white  powder  on  the  walls 
and  floors  of  the  chambers  above.* 

Properties. — "Arsenic"  is  soluble  in  hot  H20,  and  has  a 
slightly  sweetish  taste.  It  is  a  powerful  poison,  doses  of 
two  or  three  grains  being  fatal,  although  an  over-dose 
acts  as  an  emetic.  It  is  an  antiseptic,  and  so  in  cases  of 
poisoning  frequently  attracts  attention  by  the  preserva- 
tion of  parts  of  the  body,  even  twenty  or  thirty  years 
after  the  murder  has  been  committed.  The  antidote  is 
milk  or  whites  of  eggs.f 

Marsh's  Test.  —  There  is  no  other  poison  which  is 
so  easily  detected.  Prepare  a  flask  for  the  evolution  of  H. 
Ignite  the  jet  of  gas,  and  hold  in  the  flame  a  cold  porce- 
lain dish.  If  it  remains  untarnished,  the  materials  con- 
tain .no  As.  Now  pour  in  through  the  funnel-tube  a 
few  drops  of  a  solution  of  As ;  J  the  color  of  the  flame 
will  be  seen  to  change  almost  instantly,  and  a  copious 
" metallic  mirror"  of  As  will  be  deposited  on  the  dish. 


*  Its  removal  is  a  work  of  great  danger.  The  workmen  are  entirely  enveloped 
in  a  leathern  dress  and  a  mask  with  glass  eyes ;  they  breathe  through  a  moistened 
eponge,  thus  filtering  the  air  of  the  fine  particles  of  arsenic  floating  through  it. 
Yet,  in  spite  of  all  these  precautions,  they  rarely  live  beyond  forty. 

t  The  exact  chemical  antidote  is  hydrated  ferric  oxide.  In  this,  as  in  most 
other  cases  of  poisoning,  where  the  antidote  is  not  at  hand,  an  emetic  should  be 
taken  at  once — a  tea-spoonful  of  mustard  in  a  glass  of  warm  water,  or  even  a 
quantity  of  soap-suds.  (See  Physiology,  page  209.) 

J  This  is  made  by  dissolving  a  little  AsaO3  in  HCl. 


ARSENIC. 


125 


Fig.  52. 


The  gas  formed  in  this  experiment — arseniuretted  hydro- 
gen— is  'very  poisonous  indeed,  and  the  utmost  care 
should  be  used  to  pre- 
vent its  inhalation.* 

Arsenic  -JZaling. 
— It  is  said  that  the 
peasants  in  a  portion  of 
Hungary  are  accus- 
tomed to  eat  As,  both 
fasting  and  as  a  season- 
ing to  their  food.  A 
very  minute  portion 
will  warm,  stimulate, 
and  aid  in  climbing 
lofty  mountains.  The 
arsenic-eaters  are  de- 
scribed as  plump  and  rosy,  and  it  is  said  that  the  young 
people  resort  to  this  dangerous  substance,  as  a  species  of 
cosmetic.  They,  begin  with  small  doses,  which  are  grad- 
ually increased;  but  if  the  person  ceases  the  practice, 
all  the  symptoms  of  arsenic  poisoning  immediately 
appear.  Horse- jockeys  sometimes  feed  arsenic  to  their 
horses  to  improve  their  flesh  and  speed. 

*  In  a  case  of  poisoning,  of  course,  the  contents  of  the  stomach  would  be 
substituted  for  the  solution  of  As,  and  other  tests  besides  this  would  be  em- 
ployed. We  can  imagine  with  what  care  a  chemist  would  conduct  the  examin- 
ation, and  with  what  intense  anxiety  he  would  watch  the  porcelain  dish  as  the 
flame  played  upon  it,  hesitating,  and  dreading  the  issue,  as  he  felt  the  life  of  a 
fellow-being  trembling  on  the  result  of  his  experiment. 


Marsh's  Test. 


126  INORGANIC     CHEMISTRY. 


THE     METALS. 


THE    METALS    OF    THE    ALKALIES, 
K,  Na,  L,  Cs,  Rb,  and  H4N(?), 


POTASSIUM. 

Symbol,  K Atomic  Weight,  39 Specific  Gravity,  0,86, 

Source. — K  is  found  abundantly  in  the  various  rocks, 
which,  by  their  decomposition  furnish  it  to  the  plants 
from  which  we  obtain  our  entire  supply.* 

Preparation.— This  metal  was  discovered  by  Sir  Hum- 
phrey Davy,  in  1807.  On  passing  the  current  of  a  power- 
ful galvanic  battery  through  potash,  the  globules  of  the 
K  appeared  at  the  negative  pole.  The  metals  Na,  Ba,  Sr, 
and  Ca,  were  afterward  separated  in  the  same  manner. 
This  discovery  constituted  a  most  important  epoch  in 
chemistry.  K  is  now  prepared  by  distilling  in  iron  bot- 
tles, at  an  intense  heat,  potassium  carbonate  and  charcoal. 
The  green'  vapors  of  K  are  condensed  in  receivers  of 
naphtha,  and  CO  passes  off  as  a  gas.  K2C03  +  2C=K2  + 
3CO.  It  is  a  difficult  and  dangerous  process.  The  vapor 

*  "  An  acre  of  wheat  producing  twenty-five  bushels  of  grain  and  3,000  Ibs.  of 
straw,  removes  about  40  Ibs.  of  potash  in  the  crop.  An  acre  of  corn,  produc- 
ing 190  bushels,  removes  in  kernel  and  stalk  150  Ibs.  of  potash  and  80  Ibs.  of 
phosphoric  acid.  An  acre  of  potatoes,  yielding  300  bushels,  will  remove  in  tubers 
and  tops  400  Ibs.  of  potash  and  150  Ibs.  of  phosphoric  acid.  A  pound  of  wheat 
holds  a  quarter  of  an  ounce  of  mineral  substances,  and  a  pound  of  potatoes  one- 
eighth  of  an  ounce."— NICHOLS. 


POTASSIUM.  127 

takes  fire  instantly  on  contact  with  air  or  water.  It  also 
absorbs  CO,  and  the  compound,  if  kept,  becomes .  power- 
fully explosive.  To  prevent  this  danger,  the  K  is  imme- 
diately redistilled. 

Properties.— K  is  a  silvery-white  metal,  soft  enough  to 
be  spread  with  a  knife,  and  light  enough  to  float  like  cork. 
Its  affinity  for  0  is  so  great  that  it  is  always  kept  under 
the  surface  of  naphtha,  which  contains  no  0.  K,  when 
thrown  on  H20,  decomposes  it,  sets 
free  one  atom  of  H,and  forms  KHO. 
The  heat  developed  is  so  great,  that 
the  H  catches  fire  and  burns  with 
some  volatilized  K,  which  tinges  the  K  on  H  o 

flame  with  a  beautiful  purple  tint. 
If  the  H20  be  first  colored  with  red  litmus,  it  will  become 
blue  by  the  alkali  formed. 

Compounds. — Potash,  K20,  has  so  great  an  affinity  for 
H20  that  the  anhydrous  form  is  rarely  prepared.  Its 
hydrate,  KHO,f  is  a  white  solid  made  from  potassium 
carbonate  by  the  action  of  slacked  lime.  It  is  the  most 
powerful  alkali.  It  neutralizes  the  acids,  and  turns  red 
litmus  to  blue.  It  is  used  to  cauterize  the  flesh,  and  is 
hence  commonly  called  "  caustic  potash."  It  dissolves 
the  cuticle  of  the  finger  which  touches  it,  and  so  has  an 
unctuous  feel.  It  unites  with  grease,  forming  soap,  in 
the  manufacture  of  which  it  is  extensively  used. 

^Potassium  Carbonate,  K2C03,  \  Pearlash,  "  Car- 
bonate of  Potash"  is  obtained  in  the  following  manner : 

*  Cut  the  metal  in  small  pieces  and  cover  it  with  a  receiver,  since  the  melted 
globule  bursts  at  the  close  of  the  experiment. 

t  K2O+H2O=2(KHO),  or  2  molecules  of  potassium  hydrate. 

$  The  symbol  KaCO3  is  merely  a  list  of  the  elements,  and  the  proportion  of 
each  contained  in  a  molecule  of  potassium  carbonate.  It  is  called  an  empirical 


1*28  INORGANIC    CHEMISTRY. 

Potasli  exists  in  plants,  combined  with  various  acids,  such 
as  tartaric,  malic,  oxalic,  etc.  When  the  wood  is  burned, 
the  organic  acids  are  decomposed  by  the  heat,  and  the 
C02  combines  with  the  K20,  forming  K2C03.  The  ashes 
are  then  leached  and  the  lye  is  evaporated,  when  the  salt 
crystallizes.  This  forms  potassium  carbonate,  the  "  pot- 
ash" of  commerce.  "When  refined  it  is  called  "pearlash." 
Where  wood  is  abundant,  immense  quantities  are  burned 
solely  for  this  product.  Birch  gives  the  purest  potash, 
while  the  leaves  of  a  tree  furnish  twenty-five  times  as 
much  as  the  heart.* 

JBjdrogen  ^Potassium  Carbonate,  \  H  KC03,  Sal- 
eratus,  "Bicarbonate  of  Potash  "\  is  prepared  by  pass- 


formula.  It  can  be  written  thus :  KaO.COa,  and  is  then  termed  a  rational 
formula,  since  it  indicates  the  compounds  which,  put  together,  form  the  car- 
bonate. One  objection  to  the  latter  formula  is  that  we  do  not  know  that  the 
separate  compounds  still  exist  in  the  salt.  The  empirical  formula  contains  all 
that  is  positively  decided. 

*  Vast  deposits  of  potash  have  been  opened  up  to  us  at  the  Stassfurth  salt 
mines  in  Germany,  the  supply  from  which  is  more  than  from  the  wood-ash 
sources  of  the  whole  world.  "  Only  about  13,000  tons  of  potash  were  sent  to  mar- 
ket from  the  United  States  and  British  America  in  1870,  and  yet  from  Stassfurth, 
where  a  dozen  years  ago  it  was  not  supposed  that  a  single  ton  could  be  produced, 
80,000  tons  of  potassium  chloride  were  manufactured  and  supplied  to  consumers 
upon  both  continents  during  the  following  year.  The  surface  salts  at  these  mines, 
which  hold  .the  potash,  are  practically  inexhaustible,  and  millions  of  tons  will 
be  supplied  in  succeeding  years."— Fireside  Science. 

t  The  molecule  of  carbonic  acid  is  H3COS.  In  potassium  carbonate,  K2CO3, 
both  the  atoms  of  H  contained  in  the  carbonic  acid  are  replaced  by  the  metal  K ; 
in  hydrogen  potassium  carbonate,  HKCO3,  only  one  atom  of  H  is  thus  replaced. 
In  this  way  two  classes  of  salts  are  derived ;  the  so-called  acid  salts,  where  only 
one  atom  of  H  has  been  replaced,  and  the  neutral  salts,  where  both  atoms  have 
been  replaced  by  a  metal.  Thus  hydrogen  potassium  sulphite,  HKSOS,  is  an  acid 
salt,  and  potassium  sulphite,  K3SO3,  is  a  neutral  salt.  An  acid  containing  two 
atoms  of  H,  capable  of  displacement  by  a  metal,  is  said  to  be  dibasic,  as  H-.SO^, 
H2COS ;  and  one  having  three  atoms  capable  of  displacement  is  termed  tribasic. 
Example  :  HSPO4,  which  forms  three  different  salts  from  Na,  the  H  being  dis- 
placed from  the  acid  step  by  step. 

$  If  we  double  the  number  of  atoms  of  each  element  in  a  molecule  of  hydro- 
gen potassium  carbonate,  the  rational  formula  will  be  KaO.HaO.2COa ;  hence 
this  salt  is  commonly  called  the  bicarbonate  of  potash. 


POTASSIUM.  1%9 

ing  CO 2  through  a  strong  solution  of  potassium  car- 
bonate. 

^Potassium  Nitrate,  KN03,*  Nitrate  of  Potash, 
Saltpetre,  Nitre. —  This  salt  is  found  as  an  efflores- 
cence on  the  soil  in  tropical  regions,  especially  in  India, 
It  is  obtained  thence  by  leaching.f  It  is  formed  artifi- 
cially by  piling  up  great  heaps  of  mortar,  refuse  of  sinks, 
stables,  etc.  "  In  about  three  years,  these  are  washed,  and 
each  cubic  foot  of  the  mixture  will  furnish  four  or  five 
ounces  of  saltpetre."  It  dissolves  in  about  three  and  a 
half  times  its  weight  of  cold  H20. 

Properties  and  Uses. — It  is  cooling  and  antiseptic; 
hence  it  is  used  with  common  salt  (NaCI)  for  preserving 
meat.  It  parts  readily  with  its  0,  of  which  it  con- 
tains nearly  48  per  cent.,  and  deflagrates  brilliantly. 
Every  government  keeps  a  large  supply  on  hand  for 
making  gunpowder,  in  the  event  of  war.  Gunpowder  is 
composed  of  about  three  parts  charcoal,  and  one  each  of 
saltpetre  and  sulphur— the  proportion  varying  with  the 
purpose  for  and  the  country  in  which  it  is  made.  Its  ex- 
plosive force  is  due  to  the  expansive  power  of  the  gases 
formed.  At  the  touch  of  a  spark  the  saltpetre  gives  up 
its  0  to  burn  the  S  and  C.  The  reaction  that  ensues 
maybe  approximately  represented  as  follows:  2KN03-f- 
S  +  3C=K2S+N2  +  3C02. 

N  and  C02  are  gases,  and  in  the  great  heat  of  perhaps 
2,000°,  high  enough  to  melt  silver  or  copper,  the  K2S  be- 
comes a  vapor.  "With  the  sudden  increase  of  temperature 
they  all  expand  till  they  occupy  at  least  1,500  times  the 

*  In  this  salt  the  H  of  HNO,  is  replaced  by  K.    (See  page  23,  note.) 

t  It  was  manufactured  in  the  Mammoth  Cave,  Kentucky,  during  the  war  of 

1812.    The  remains  of  the  works,  and  even  the  deep  ruts  of  the  wagon-wheels, 

are  still  to  be  seen,  preserved  in  the  pure,  still  air. 


130  INORGANIC    CHEMISTRY. 

space  of  the  powder.-^MiLLER.  The  bad  odor  of  burnt 
powder  is  due  to  the  slow  formation  of  H2S  in  the  resid- 
uum. Fireworks  are  composed  of  gunpowder  ground 
with  additional  C  and  S,  and  some  coloring  matter.  Zinc 
filings  produce  green  stars,  steel  filings  variegated  ones. 
Sr2N03  tinges  flame  with  crimson.  Salts  of  copper  give 
a  blue  or  green  light,  and  camphor  a  pure  white  one. 

(Potassium  Ch2orate,  KC103,  is  a  white,  crystallized 
salt  much  used  in  preparing  oxygen,  making  matches, 
fireworks,  etc.  It  is  a  powerful  oxydizing  agent* 

(Potassium  ^Bichromate  \  is  a  red  salt  highly 
valued  in  dyeing,  calico-printing,  and  photo-lithography. 
If  we  mix  a  solution  of  this  salt  and  one  of  sugar  of  lead, 
a  yellow-colored  precipitate  will  be  formed,  known  in  the 
arts  as  chrome-yellow  (lead  chromate). 


SODIUM. 

Symbol,  Na Atomic  Weight,  23 Specific  Gravity,  0.972, 

THIS  metal  is  found  principally  in  common  salt.  Its 
preparation  is  similar  to  that  of  K,  but  is  more  easily 
managed.  It  is  very  like  K  in  appearance,  properties, 

*  Examples :  1.  Cover  a  bit  of  phosphorus,  no  larger  than  a  mustard  seed, 
with  finely  powdered  KC1O3  (See  Appendix),  wrap  in  a  paper  and  lay  it  on  an 
anvil.  Upon  striking  the  mixture  with  a  hammer,  a  sharp  detonation  will 
ensue.  2.  Place  in  a  wine-glass  five  or  six  pieces  of  phosphorus  as  large  as  a 
grain  of  wheat,  and  cover  with  crystals  of  KC1O3.  Fill  the  glass  two-thirds  full 
of  HaO.  By  means  of  a  pipette,  or  a  glass  funnel,  introduce  into  immediate  con- 
tact with  the  KC1O3  a  few  drops  of  strong  H2SO4.  A  violent  chemical  action 
will  immediately  ensue,  and  the  phosphorus  will  burn  under  the  water  with  vivid 
flashes  of  light. 

t  Chromic  anhydride (CraOs)  is  an  oxide  of  chromium  (chroma,  color),  a  metal 
prized  only  for  its  numerous  brilliantly  colored  compounds.  It  is  rather  rare, 
and  mainly  found  in  chrome  iron-stone  (FeO.Cr9Os). 


SODIUM.  181 

and  reaction.-  "When  thrown  on  H20  it  rolls  over  its  sur- 
face like  a  tiny  silver  ball ;  if  the  H20  be  heated,  it  bursts 
into  a  bright  yellow  blaze.  The  test  of  all  the  soda  salts 
is  the  yellow  tint  which  their  solution  in  alcohol  gives  to 
flame. 

Compounds.  —  Sodium  Chloride,  NaCl,  Common 
Salt,  is  a  mineral  substance  absolutely  necessary  to  the 
life  of  human  beings  and  the  higher  orders  of  animals. 
It  does  not  enter  into  the  composition  of  tissue,  but  is 
essential  to  the  proper  digestion  of  the  food  and  to  the 
removal  of  worn-out  matter.  (See  Physiology,  p.  137.) 
Among  the  many  cruel  punishments  inflicted  in  China, 
deprivation  of  salt  is  said  to  be  one,  causing  at  first  a 
most  indescribable  longing  and  anxiety,  and  finally  a 
painful  death.  As  salt  is  so  universally  necessary,  it  is 
found  everywhere.  Our  Father,  in  fitting  up  a  home  for 
us,  did  not  forget  to  provide  for  all  our  wants.  The  quan- 
tity of  salt  in  the  ocean  is  said  to  be  equal  to  five  times 
the  mass  of  the  Alps.  Salt  lakes  are  scattered  here  and 
there ;  saline  springs  abound ;  and  besides  these,  in  the 
earth  are  stored  great  mines,  probably  produced  by  the 
evaporation  of  salt  lakes  in  some  ancient  period  of  the 
earth's  history.  Near  Cracow,  Poland,  is  a  bed  five  hun- 
dred miles  long,  twenty  miles  wide,  and  a  quarter  of  a 
mile  thick.  In  Spain,  and  lately  in  Idaho,  it  has  been 
quarried  out  in  perfect  cubes,  transparent  as  glass,  so  that 
a  person  can  read  through  a  large  block. 

Preparation. — On  the  sea-shore  it  is  manufactured  by 
the  evaporation  of  sea-water,  each  gallon  containing 
about  four  ounces.*  At  Syracuse,  New  York,  near  by 

*  Salt  is  soluble  in  less  than  three  times  its  weight  of  HaO.    It  dissolves 
equally  well  in  hot  or  cold  H2O,  and  a  saturated  solution  (one  containing  all  it 


132 


INOR&ANIC     CHEMISTRY. 


and  underneath  the  Onondaga  Lake,  is  apparently  a 
great  basin  of  salt-water,  separated  from  the  fresh -water 
above  by  an  impervious  bed  of  clay.  Upon  boring 
through  this,  the  saline  water  is  pumped  up  in  immense 
quantities.  The  H20  is  evaporated  by  heating  in  large 
iron  kettles  over  a  fire,  or  in  shallow,  wooden  vats  by 
exposure  to  the  sun — whence  the  name  "solar  salt." 
If  boiled  down  rapidly,  fine  table-salt  is  made ;  if  more 
slowly,  coarse  salt,  as  large  crystals  have  time  to  form. 
Frequently  they  assume  a  "hopper  shape,"  one  cube 

Hg.  5U. 


Hopper  form  of  sail  crystals. 

appearing,  then  others  collecting  at  its  edges,  and  gradu- 
ally settling,  until  a  hollow  pyramid  of  salt-cubes,  with 
its  apex  downward,  is  formed. 

Uses. — NaCl  is  used  largely  as  a  fertilizer,  for  preserv- 
ing meats  and  fish,  and  for  preparing  Cl,  HC1,  and  the 
various  compounds  of  Na. 

will  dissolve)  has  about  36  per  cent.  Sea-water  contains  about  3  per  cent. 
Sodium  carbonate  was  formerly  obtained  from  the  ashes  of  sea-planta,  as  potas- 
•ium  carbonate  ia  now  from  the  ashes  of  land-plants.— ROSCOE. 


SODI UM.  138 

Sodium  Sulphate  (Na2S04, 10H20),  Glauber's  Salt, 
named  from  its  discoverer,  is  made  in  great  quantities 
from  NaCl,  as  the  first  stage  in  the  manufacture  of  sodium 
carbonate.  It  is  remarkably  efflorescent,  the  salt,  by 
exposure  to  the  air,  losing  its  ten  molecules  of  H20.*  It 
has  a  bitter,  saline  taste  and  is  used  in  medicine. 

Sodium  Carbonate  (Na2C03, 10H20),  Sal-soda,  is 
used  extensively  in  the  arts.  It  is,  therefore,  of  great 
importance  to  all  consumers  of  soap,  glass,  etc.,  that  it 
should  be  manufactured  as  cheaply  as  possible.  Le- 
blanc's  process  of  making  it  from  NaCl  is  now  gen- 
erally adopted.  The  operation  comprises  two  stages: 
Changing,  1.  NaCl  into  Na2S04;  and,  2.  Na2S04  into 
Na2C03. 

1.  A  mixture  of  NaCl  and  H2S04  is  heated.     Na2S04 
is  formed  with  a  copious  evolution  of  HC1.    The  fumes 
of  this  gas  are  conducted  into  the  bottom  of  a  vertical 
flue  filled  with  pieces  of  coke  wet  with  constantly  falling 
H20.    The  gas  is  here  absorbed  and  a  weak  muriatic  acid 
formed  in  great  quantities.f 

2.  The  Na2S04  is  heated  with  chalk  (CaC03)  and  char- 
coal*.  The  C  deoxidizes  the  Na2S04,  changing  it  into  Na2S. 
The  metals  of  the  Na2S  and  the  CaC03  change  places, 


*  Experiment :  Make  a  saturated  solution  of  sodium  sulphate,  and  with  it  fill 
a  bottle.  Either  put  in  the  glass  stopple  or  cover  the  top  with  a  thin  layer  of  oil, 
and  let  the  bottle  stand.  The  salt  will  remain  for  months  without  crystallizing; 
but  if  it  be  taken  up,  and  shaken  ever  so  little,  the  whole  mass  will  instantly 
form  into  crystals,  so  filling  the  bottle  that  not  a  drop  of  water  will  escape,  even 
if  it  be  inverted.  Should  there  be  any  hesitation  in  crystallizing  at  the  moment, 
drop  into  the  bottle  a  minute  crystal  of  the  salt,  and  the  effect  will  instantly  be 
seen  in  the  darting  of  new  crystals  in  every  direction. 

t  This  acid  was  formerly  allowed  to  escape,  causing  the  destruction  of  all 
vegetation  in  the  neighborhood.  It  is  now,  however,  absorbed  so  perfectly  that 
the  gases  which  escape  from  the  top  of  the  chimney  will  not  render  turbid  a 
solution  of  silver  nitrate  (see  page  166),  showing  that  there  is  not  a  trace  of  the 
acid  left. 


134  INORGANIC     CHEMISTRY. 

forming  Na2C03  and  CaS.  Out  of  this  mass,  called  from 
its  color  "black-ash,"  the  Na2C03  is  dissolved,*  and  then 
crystallized,. making  the  "soda- ash"  of  commerce. ' 

Hydrogen  Sodium  Carbonate  (HNaC03),t  "Bi- 
carbonate of  Soda"  is  the  "soda"  of  the  cook-room. 
It  is  prepared  by  the  action  of  C02  on  sodium  carbonate. 
The  CO  2  may  be  easily  liberated  by  the  action  of  an  acid. 
(See  p.  234.) 


AMMONIUM. 
Symbol,  H4N Molecular  Weight,  18, 

THIS  is  a  compound  which  has  never  been  separated,  but 
it  is  generally  thought  to  be  the  base  of  the  salts  formed 
by  the  action  of  the  acids  upon  the  alkali  ammonia,  which 
in  form,  color,  and  lustre  closely  resemble  the  corres- 
ponding salts  of  K.  The  analogy  between  its  action  and 
that  of  the  simple  metals  is  so  yery  striking  J  that  it  is 
considered  a  compound  metal,  acting  the  part  of  a  simple 
one,  as  Cy  does  that  of  a  compound  halogen  (see  p.  84).  § 


*  The  insoluble  residuum  of  CaS,  and  the  superfluous  coal,  form  around  the 
alkali  works  a  mountain  of  waste.  Attempts  have  been  made  to  extract  the  S, 
and  at  the  Paris  exposition  large  blocks  thus  obtained  were  exhibited ;  but  the 
operation  has  failed  of  commercial  success. 

t  The  rational  formula  (see  note,  page  127)  is  Na3O.HaO.2CO2,  whence  the 
name  bicarbonate  of  soda.  » 

$  When  H3N  is  dissolved  in  H2O,  forming  H3N.H2O,  the  compound  may  be 
represented  as  (H4N)  HO.  Comparing  this  with  the  formula  for  caustic  potash, 
KHO,  we  see  that  the  group  of  elements  H4N  corresponds  to  the  K.  Thus  we 
may  call  a  solution  of  H3N,  ammonium  hydrate,  as  one  of  potash  is  a  potassium 
hydrate.  Both  act  as  powerful  bases,  neutralize  the  acids  and  form  soaps. 

§  The  following  experiment  is  thought  by  some  to  be  an  additional  proof  of 
the  metallic  nature  of  this  compound  substance.  Heat  moderately  in  a  test-tube 
half  a  fluid-dram  of  Hg  with  a  piece  of  Na  the  size  of  a  pea.  The  two  metals 


AMMONIUM.  135 

Compounds  — Ammonium  Chloride,  H4NC1,*  Sal- 
ammoniac,  is  prepared  from  the  ammoniacal  liquor  of 
the  gas-works.  (See  p.  83.)  Its  tough  fibrous  crystals 
reveal  no  trace  of  the  pungent  ammonia,  yet  it  can  easily 
be  set  free,  as  we  have  already  seen  (p.  48).  Sal-ammo- 
niac is  soluble  in  H20.  It  is  used  in  medicine,  in  the 
preparation  of  H3N  and  its  salts,  in  dyeing,  and  also  in 
soldering,  as  it  dissolves  the  coating  of  the  oxide  of  the 
metal  and  preserves  the .  surfaces  clear  for  the  action  of 
the  solder. 

Ammonium  Carbonate,  Sal-volatile,  Smelling  Salts, 
is  prepared  by  the  action  of  chalk  upon  sal-ammoniac,  f 
It  is  largely  used  by  bakers  in  raising  cake.  (See  p.  235.) 

Ammonium  Nitrate  (H3N,HN03=H4N,N03)  may 
be  readily  formed  by  cautiously  adding  dilute  HN03 
to  aqua  ammonia  until  the  liquid  becomes  neutral,  and 
then  evaporating.  Long,  needle-shaped  crystals  will 
form.  Thus  two  fiery  liquids  combine' to  produce  a  solid 
having  no  resemblance  to  either  of  them.  By  heat  this 
salt  may  be  converted  into  H20  and  N20.  (See  p.  46.) 

will  combine,  forming  a  pasty  amalgam.  When  cold,  pom-  over  it  a  solution  of 
sal-ammoniac.  The  amalgam  will  immediately  swell  up  to  eight  or  ten  times 
its  original  "bulk,  retaining \  however,  Us  metallic  lustre.  The  ammonium  cannot 
be  separated  from  the  amalgam,  since,  on  heating,  it  decomposes,  and  on  being 
thrown  into  water,  H  is  set  free  and  H3N  formed. 

*  Its  rational  formula  is  H3N.HC1,  whence  it  is  often  called  hydrochlorate  of 
ammonia. 

t  It  is  a  sesquicarbonate,  but  by  the  constant  loss  of  H3N  through  evapora- 
tion, it  becomes  crusted  with  a  spongy  coat  of  the  "bicarbonate,"  hydrogen 
ammonium  carbonate  (H4N),  HCO3. 


136 


INORGANIC     CHEMISTRY. 


METALS  OF  THE  ALKALINE  EARTHS, 

Ca,  Ba,  and  Sr, 


Fig.  55. 


CALCIUM. 

Symbol,  Ca Atomic  Weight,  40 Specific  Gravity,  1,57, 

Ca  exists  abundantly  in  limestone,  gypsum,  and  in  the 
bones  of  the  body.*  It  commonly  occurs  as  an  oxide  or 
a  carbonate. 

Compounds. — Ca2cium    Oxide  (CaO),   Caustic  or 

Quicklime,  is  obtained  by 
heating  limestone  (CaC03) 
in  large  kilns.  The  C02  is 
driven  off  by  the  heat,  and 
the  CaO  is  left  as  a  white 
solid. 

Fig.  55  shows  a  form  of 
lime-kiln  in  which  the  pro- 
cess is  continuous.  At  #, 
b,  c,  d,  are  the  doors  for  the 
fuel,  ash-pit,  etc.  The  lime- 
kiln is  fed  at  the  top  from 
time  to  time,  while  the  lime 
is  taken  out  at  /  as  fast  as 

Lame-kiln.  * 

formed. 

Properties. —  CaO  is  a  strong  alkali,  and  corrodes  the 
flesh.  Its  test  is  C02,  producing  a  milky  precipitate  of 


*  "  There  are  5  Ibs.  of  phosphate  of  lime,  one  of  carbonate  of  lime,  and  3  oz. 
of  fluoride  of  calcium  in  the  body  of  an  adult  weighing  154  Ibs."— NICHOLS. 


CALCIUM.  187 

CaC03.  It  has  such  an  affinity  for  H20,  that  fifty-six 
pounds  of  lime  will  absorb  eighteen  pounds  of  H20, 
forming  CaO,H20,  or  "slacked  lime,"  and  expanding 
to  several  times  its  original  size,  with  the  evolution  -of 
much  heat.  CaO  absorbs  H20  from  the  air,  and  then 
C02,  thus  gradually  becoming  "air-slacked  lime."  It  is 
sparingly  soluble  in  water.  A  thin  film  of  calcium  car- 
bonate will  soon  gather  over  a  solution  of  lime  exposed 
to  the  air.  Water-lime  contains  a  little  clay  and  will 
harden  under  water. 

Uses. —  Whitewash  is  a  "milk  of  lime,"  i.  e.,  lime  dif- 
fused through  water.  Concrete  is  a  cement  of  coarse 
gravel  and  water-lime.  It  is  of  great  durability.  Hard 
finish  is  a  kind  of  plaster  in  which  gypsum  is  used  to 
make  the  wall  smooth  and  hard.  Calcimine  is  a  variety 
of  whitewash  made  of  whiting  or  plaster  of  Paris.  Mor- 
tar is  a  mixture  of  lime  and  sand  wet  with  H20.  It 
hardens  rapidly,  by  absorbing  C02  from  the  air  to  form 
a  carbonate,  and  partly,  perhaps,  by  uniting  with  the 
Si02  of  the  sand  to  form  a  silicate.* 

Lime  is  valuable  as  a  fertilizer.  It  acts  by  rapidly  de- 
composing all  vegetable  matter,  and  thus  forming  H3N 
for  the  use  of  plant s.f  It  also  sets  free  the  alkalies 

*  "  If  common  mortar  be  protected  from  the  air,  it  will  remain  without  harden- 
ing for  many  years.  It  is  stated  that  lime  still  in  the  condition  of  a  hydrate  has 
been  found  in  the  Pyramids  of  Egypt.  When  the  ruins  of  the  old  castle  of 
Landsberg  were  removed,  a  lime-pit,  that  must  have  been  in  existence  three 
hundred  years,  was  found  in  one  of  the  vaults.  The  surface  was  carbonated  to 
the  depth  of  a  few  inches,  but  the  lime  below  this  was  fresh  as  if  just  slacked, 
and  was  used  in  laying  the  foundations  of  the  new  building.'1— American  Cyclo- 
pedia. 

t  If  applied  to  a  compost  heap,  it  will  set  free  H3N,  thus  robbing  it  of  its 
most  valuable  constituent.  This  can  be  saved  by  sprinkling  the  pile  with  dilute 
H2SO4,  or  plaster,  or  by  mixing  it  with  dry  muck,  which  will  absorb  the  gas. 
If  there  is  any  copperas  (produced  by  the  oxidation  of  iron  pyrites)  in  the  soil, 
the  lime  will  decompose  it,  forming  gypsum  and  iron-rust,  thus  changing  a 
noxious  ingredient  into  an  element  of  fertility. 


138  IN  ORGANIC     CHE  MIS  TR  Y. 

that  are  combined  in  the  soil,  and  furnishes  them  to  the 
plants,  becoming  itself  a  carbonate.  Lime  is  also  used 
extensively  in  the  preparation  of  bleaching  powder,  in 
refining  sugar,  in  making  candles,  in  tanning,  and  in  the 
manufacture  of  coal-gas. 

Fig.  56. 


A  cave  with  stalactites  and  stalagmites. 

Calcium  Carbonate,  CaC03,  includes  limestone, 
chalk,  marble,  and  marl,  and  forms  the  principal  part  of 
corals,  shells,  etc.  H20  charged  with  C02  dissolves 
CaC03  freely,  which,  when  the  gas  escapes  on  exposure 
to  the  air,  is  deposited.  In  limestone  regions,  the  water 
trickling  down  into  caverns  has  formed  "stalactites," 


CALCIUM.  139 

which  depend  from  the  ceiling,  and  "  stalagmites,"  that 
rise  from  the  floor.  These  frequently  assume  curious 
and  grotesque  forms,  as  in  the  Mammoth  Cave.  Around 
many  springs,  the  water,  charged  with  CaC03  in  solution, 
flows  over  moss  or  some  vegetable  substance,  upon  which 
the  stone  is  deposited.  The  spongy  rock  thus  formed  is 
called  calcareous  tufa,  or  "  petrified  moss."  (See  Geology, 
p.  49.)  Marble  is  crystallized  limestone.  Chalk  or  marl 
is  a  porous  kind  of  limestone,  formed  from  beds  of  shells, 
but  not  compressed  as  in  common  limestone.  Whiting  is 
ground  chalk. 

Calcium  Su2p?iale  (CaS04,2H20),  Gypsum,  Plas- 
ter, etc.* — This  occurs  as  beautiful  fibrous  crystals  in  satin 
spar,  as  transparent  plates  in  selenite,  and  as  a  snowy- 
white  solid  in  alabaster.  It  is  soft,  and  can  be  cut  into 
rings,  vases,  etc.  When  heated  it  loses  its  water  of  crys- 
tallization, and  is  ground  into  powder,  called  "  Plaster  of 
Paris,"  from  its  abundance  near  that  city.  Made  into  a 
paste  with  H20,  it  first  swells  up,  and  then  immediately 
hardens  into  a  solid  mass.  This  property  fits  it  for  use 
in  copying  medals  and  statues,  forming  moulds,  fastening 
metal  tops  on  glass  lamps,  etc.  Plaster  (unburned  or 
hydrated  gypsum)  is  used  as  a  fertilizer,  f  Its  action  is 
probably  somewhat  like  that  of  lime,  and  in  addition  it 
gathers  up  ammonia  and  holds  it  for  the  plant. 


*  The  rational  formula  is  CaO.SO3 ;  hence  it  is  commonly  called  "  sulphate  of 
lime."  Comparing  the  formula  H3SO4  and  CaSO4,  we  see  that  one  atom  of  Ca 
can  replace  two  atoms  of  H  ;  it  is  therefore  one  of  a  class  of  elements  called 
dyads  (duo,  two).  An  atom  of  K,  as  we  have  seen,  can  displace  only  one  atom 
of  H  ;  it  belongs  to  the  monads  (monos,  alone). 

t  It  is  said  that  Franklin  brought  CaSO4  into  use  by  sowing  it  over  a  field  of 
grain  on  the  hill-side,  so  as  to  form,  in  gigantic  letters,  the  sentence,  "  Effects  of 
gypsum."  The  rapid  growth  produced  soon  brought  out  the  words  in  bold 
relief,  and  decided  the  destiny  of  gypsum  among  farmers. 


INORGANIC     CHEMISTRY. 

Calcium  Sulphite,  CaS03,  should  be  distinguished 
from  the  sulphate.  It  is  much  used  in  preserving  cider, 
being  sold  as  "  sulphite  of  lime." 

Calcium  ^Phosphate,  "  Phosphate  of  Lime"  is  fre- 
quently termed  lone  phosphate,  as  it  is  a  constituent  of 
bones.  (See  p.  120.)  It  is  found  in  New  Jersey,  South 
Carolina,*  and  Canada.  It  is  the  valuable  part  of  certain 
guanos.  Fertilizers  are  prepared  by  treating  ground 
bones  with  H2S04,  forming  the  so-called  superphosphate 
of  lime.f  This  is  a  mixture  of  gypsum  and  hydrogen 
calcium  phosphate.  The  latter  furnishes  phosphorus  to 
the  growing  plant  to  store  in  its  seeds. — Example :  corn, 
wheat. 


STRONTIUM    AND    BARIUM. 

THESE  metals  are  very  like  Ca.  The  salts  of  Ba  give  a 
green  tint  to  a  flame  and  those  of  Sr  a  beautiful  crimson ; 
and  are  hence  much  used  in  pyrotechny.  Barium  sul- 
phate, commonly  called  barytes,  is  found  as  a  white  min- 
eral, noted  for  its  weight,  whence  it  is  often  termed  heavy 
spar.  Indeed,  the  term  barium  is  derived  from  a  Greek 
word ,  meaning  heavy.  This  mineral  is  largely  used  for 
adulterating  white-lead.  BaCl2  is  a  test  for  H  2S04.  (See 
p.  117.) 

*  Along  the  coast  of  South  Carolina  are  millions  of  tons  of  rocks  holding  this 
important  element  of  plant-food.    The  phosphatic  beds  extend  over  an  area  of 
several  hundred  square  miles,  and  in  some  cases  they  are  twelve  feet  thick.    It 
is  estimated  that  from  500  to  1000  tons  underlie  each  acre.— Fireside  Science. 

*  Cas2PO4  (tricalcium  phosphate)  +  2H2SO4=H\Ca2PO4  (acid  phosphate  or 
superphosphate)  +  2CaSOt  (calcium  sulphate).    As  the  gypsum  is  only  slightly 
soluble  in  water,  the  superphosphate  maybe  removed  from  the  mass  by  filtering, 
and  used  as  a  fertilizer,  or  be  heated  with  charcoal  to  form  phosphorus.    In  that 
case  it  is  reconverted  into  tricalcium  phosphate  while  a  part  of  the  phosphoric 
acid  breaks  up  thus :  4H3PO4  +16C=P4  +6Ha  +16CO. 


MAGNESIUM.  lJf.1 

MAGNESIUM.* 

Symbol,  Mg Atomic  Weight,  24,3 Specific  Gravity,  1,7, 

Source. — Mg  is  found  in  augite,  hornblende,  meer- 
schaum, soap-stone,  talc,  serpentine,  dolomite,  and  other 
rocks.  Its  salts  give  the  bitter  taste  to  sea- water.  When 
pure,  it  has  a  silvery  lustre  and  appearance.  It  is  very 
light  and  flexible.  A  thin  ribbon  of  the  metal  will  take 
fire  from  an  ignited  match,  when  it  will  burn  with  a 
brilliant  white  light,  casting  dense  shadows  through  an 
ordinary  flame,  and  depositing  flakes  of  MgO.  This  light 
possesses  the  actinic  or  chemical  principle  so  perfectly, 
that  it  is  used  for  taking  photographs  at  night,  views  of 
coal  mines,  interiors  of  dark  churches,  etc.  It  has  every 
ray  of  the  spectrum,  and  so  does  not,  like  gas-light, 
change  some  of  the  colors  of  an  object  upon  which  it 
falls.  Magnesium  lanterns  are  much  used  for  purposes 
of  illumination.  By  means  of  clockwork,  the  metal,  in 
the  form  of  a  narrow  ribbon,  is  fed  in  front  of  a  concave 
mirror,  at  the  focus  of  which  it  burns.  It  is  hoped  that 
the  process  of  manufacture  f  may  be  cheapened,  so  that 
Mg  may  be  furnished  at  a  rate  which  will  bring  it  within 
the  scope  of  the  arts. 

Compounds.  —  Magnesium    Carbonate,  MgC03, 

*  Mg  is  now  usually  classified  with  Zn,  Cd,  and  In,  since,  while  the  metals  of 
the  alkaline  earths  decompose  H2O  with  avidity  and  set  H  free,  these  four  act 
only  upon  steam  at  a  red  heat,  being  without  effect  upon  HaO  at  ordinary  tem- 
peratures. Mg  is  treated  here  for  convenience,  while  Zn  is  described  among 
the  common  or  useful  metals.  Cd  and  In  are  of  no  practical  value.  The  oxide 
of  Mg  has  a  slight  alkaline  reaction,  and  until  recently,  Mg  was  considered  one 
of  the  metals  of  the  alkaline  earths. 

t  It  is  now  prepared  by  heating  MgCla  with  metallic  Na. 


143  INORGANIC     CHEMISTRY. 

is  the  "  magnesia  alba  "  or  common  magnesia  of  the  drug- 
gist. Magnesium  sulphate  (MgS04,7H20)  is  known  as 
Epsom  salt,  from  a  celebrated  spring  in  England  in 
which  it  abounds. 


ATOMIC    EQUIVALENCE* 

T/ie  Quantiralence  of  an  J?2ement  is  its  power 
of  combining  with  H.  Thus,  if  we  examine  the  com- 
pounds HC1,  H20,  H3N  and  H4C,  we  find  the  molecule 
of  each  has  respectively  1,  2,  3,  4  atoms  of  H ;  and  we 
conclude  that  the  elements  Cl,  0,  N  and  C  have  differ- 
ent powers  of  combination  whereby  they  can  unite  with  a 
different  number  of  H  atoms.  The  same  principle  holds 
throughout  all  the  elements.  They  are  therefore  divided 
into  classes  according  to  their  power  of  combining  with  H, 
and  are  termed  respectively,  monatomic,  diatomic,  triatomic, 
&c.,  or  monads,  dyads,  triads,  &c.  (Note, p.  139.)  Each  atom 
is  supposed  to  have  a  certain  number  of  bonds  or  more  prob- 
ably poles,  like  those  of  a  magnet,  by  which  it  holds  or  be- 
comes united. to  other  atoms.  H,  Na,  Cl  have  but  one  bond 
or  pole  and  can  therefore,  like  all  monads,  only  form  pairs. 
0  has  two  poles  and  can  combine  with  H2,  an  atom  of  H  at 
each  pole,  or  with  K2  or  HC1,  or  with  an  atom  of  some  other 
dyad,  as  Zn.  (Table,  p.  288.)  C  has  four  poles  and  can  unite 
with  H4  or  C14,  or  02,  or  C120  or  H20  ;  i.  e.  with  four  atoms 
of  a  monad,  two  of  a  dyad,  or  one  of  a  dyad  and  two  of  a 
monad.  The  quantivalence  of  an  element  is  commonly 
represented  thus,  Cl1,  O11. 

*  For  a  full  explanation  of  this  subject  see  that  delightful  work  Cooke's  New 
Chemistry,  Hoffman's  Modern  Chemistry  or  Wurtz's  Introduction  to  Chemistry. 


A  L  U  MI  NUM. 


METALS    OF    THE    EARTHS. 

Al,  G,  E,  Y,  Ce,  La,  D, 


ALUMINUM. 
Symbol,  Al Atomic  Weight,  27,5 Specific  Gravity,  2,6, 

Source. — Al  is  named  from  alum,  in  which  it  occurs. 
It  is  also  called  the  "clay  metal."  It  is  the  metallic  base 
of  clay,  mica,  slate,  and  feldspar  rocks.  Next  to  0  and 
Si,  it  is  probably  the  most  abundant  element  of  the  earth's 
crust.  It  is  a  bright,  silver-white  metal ;  does  not  oxidize 
in  the  air,  nor  tarnish  by  H2S.  It  gives  a  clear  musical 
ring ;  is  only  one-fourth  as  heavy  as  Ag ;  is  ductile,  mal- 
leable, and  tenacious.  It  readily  dissolves  in  HC1,  and  in 
solutions  of  the  alkalies,  but  with  difficulty  in  HN03  and 
H2S04.  On  account  of  its  abundance  (every  clay-bank 
is  a  mine  of  it)  and  useful  properties,  it  must  ultimately 
come  into  common  use  in  the  arts  and  domestic  life. 

Compounds. — Aluminum  Oxide  (A1203). — Alumina, 
crystallized  in  nature,  forms  valuable  Oriental  gems. 
They  are  variously  colored  by  the  oxides ; — blue,  in  the 
sapphire ;  green,  in  the  emerald ;  yellow,  in  the  topaz ; 
red,  in  the  ruby.  Massive,  impure  alumina  combined  with 
magnetic  iron,  is  called  emery,  and  used  for  polishing. 

Aluminum  Silicate  (Al203,2Si02),  Silicate  of 
Alumina,  Common  Clay. — When  the  clay  rocks  decay, 
by  the  resistless  and  constant  action  of  the  air,  rain, 
and  frost,  they  crumble  into  soil.  This  contains  clay, 
silica,  and  other  impurities,  such  as  lime,  magnesia, 


144 


INORGANIC     CHEMISTRY. 


Fig.  58. 


oxide  of  iron,  etc.  The  clay  gives  firmness  to  the  soil, 
and  retains  moisture,  but  is  cold  and  tardy  in  producing 
vegetable  growth.  When  free  from  Fe,  it  is  used  for 
making  tobacco-pipes.  When  colored  by  ferric  oxide,  it 
is  known  as  ochre,  and  is  employed  in  painting.  Com- 
mon stone  and  red  earthen-ware  are  made  from  coarse 
varieties  of  clay;  porcelain  and  china-ware  require  the 
purest  material.  Fire-bricks  and  crucibles  are  made  from 
a  clay  which  contains  much  Si02-  Fullers'  earth  is  a  very 
porous  kind,  and  by  capillary  attraction  absorbs  grease 
and  oil  from  cloth. 

Glazing.  —  When  any  article  of  earthen- ware  has 
been  moulded  from  clay,  it  is  baked.  As  the  ware  is 
porous,  and  will  not  hold  H20, 
a  mixture  of  the  coarse  materials 
from  which  glass  is  made  is  then 
spread  over  the  vessel,  and  heated 
till  it  melts  and  forms  a  glazing 
upon  the  clay.  Ordinary  stone- 
ware is  glazed  by  simply  throw- 
ing damp  NaCl  into  the  fur- 
nace. This  volatilizes,  and  being 
decomposed  by  the  hot  clay  makes 
a  sodium  silicate  over  the  surface, 
while  fumes  of  HC1  escape.  Pb  is 
sometimes  used  to  give  a  yellowish 
glaze,  which  is  very  injurious,  as 
it  will  dissolve  in  vinegar,  and  form  sugar  of  lead,  a 
deadly  poison.  The  color  of  pottery-ware  and  brick  is 
due  to  the  oxide  of  iron  present  in  the  clay.  Some  varie- 
ties have  no  iron,  and  so  form  white  ware  and  brick. 
Ahim  is  made  by  treating  clay  with  H2S04,  forming 


Baldng  Porcelain. 


SPECTRUM    ANALYSIS. 

an  aluminum  sulphate.  On  adding  potassium  sulphate 
a  double  salt  is  produced,  which  separates  in  beautiful 
octahedral  crystals  (A12K24S04  +  24H20).  Instead  of  K 
an  ammonium  salt  *  is  now  generally  added,  and  an  am- 
monium alum  made,  which  takes  the  place  of  the  former 
in  the  market,  f  Alum  is  much  used  in  dyeing.  It 
unites  with  the  coloring  matter,  and  binds  it  to  the  fibres 
of  the  cloth.  It  is  therefore  called  a  mordant  (mordeo, 
to  bite). 


SPECTRUM      ANALYSIS. 


of  the  metals  named  as  rare  have  been  recently 
discovered  by  what  is  termed  Spectrum  Analysis.  We 
have  already  noticed  that  various  metals  impart  a  peculiar 
color  to  flame;  thus  Na  gives  a  yellow  tinge,  copper  a 
green,  etc.  If  now  we  look  at  these  colored  flames 
through  a  prism,  we  shall  find,  instead  of  the  "spec- 
trum "  we  are  familiar  with,  a  dark  space  strangely  orna- 
mented with  bright-tinted  lines.  Thus  the  spectrum  of 
Na  has  one  double,  yellow  line;!  Ag,  two  green  lines; 
Cs,  a  beautiful  blue  line.  Each  metal  makes  a  distinc- 
tive spectrum,  even  when  the  flame  is  colored  by  several 
substances  at  once.  This  method  of  analysis  is  so  deli- 


*  Ammonium  sulphate,  from  the  ammoniacal  liquor  of  the  gas-works.  (See 
page  83.) 

t  There  are  a  large  number  of  other  alums  known,  in  which  the  isomorphous 
sesquioxides  of  iron,  chromium,  and  manganese  are  substituted  for  the  alumina 
in  common  alum :  all  these  alums  occur  in  regular  octahedra,  and  cannot  be  sep- 
arated by  crystallization  when  present  in  solution  together. 

$  The  yellow,  sodium  line  consists  of  two  lines  lying  so  closely  together  as  to 
seem  as  one.  They  correspond  to  Fraunhofer's  lines  D  (see  Frontispiece,  No.  2), 
as  given  in  the  drawings  of  Kirchhoff  and  Bunsen. 

7 


146  INORGANIC     CHEMISTRY. 

cate  that  Tsu,uUTj™  of  a  grain  of  Na>  or  B,iroi,Tnro  of  L, 
can  be  detected  in  the  flame  of  an  alcohol  lamp  ;*  while  a 
substance  exposed  to  the  air  for  a  moment  even  will  give 
the  Na  lines  from  the  dust  it  gathers.  L  has  thus  been 
found  to  exist  in  tea,  tobacco,  milk,  and  blood,  although 
in  such  minute  quantities  as  to  have  eluded  detection  by 
former  methods  of  analysis. 

PRACTICAL     QUESTIONS. 

1.  In  the  experiment  with  Na2S04  on  page  133,  an  accurate  ther- 
mometer will  show  that  in  making  the  solution,  the  temperature  of 
the  liquid  will  fall,  and  in  its  solidification,  will  rise.  Explain. 

2.  If,  in  making  the  solution  of  Na2S04,  we  use  the  salt  which 
has  effloresced,  and  so  become  anhydrous,  the  temperature  will 
rise  instead  of  falling  as  before.  Explain. 

3.  Why  is  KNO3  used  instead  of  NaN03  for  making  gunpowder? 

4.  Why  is  a  potassium  salt  preferable  to  a  sodium  one  in  glass- 
making  ? 

5.  What  is  the  glassy  slag  so  plentiful  about  a  furnace  ? 

6.  State  the  formulae  of  nitre,  saleratus,  carbonate  and  bicarbonate 
of  soda,  plaster,  pearlash,  saltpetre,  plaster  of  Paris,  gypsum,  car- 
bonate and  bicarbonate  of  potash,  sal-soda,  and  soda. 

7.  Explain  how  ammonium  carbonate  is  formed  in  the  process 
of  making  coal-gas. 

8.  Upon  what  fact  depends  the  formation  of -(stalactites  ? 

9.  Why  is  HF  kept  in  gutta-percha  bottles  ? 

10.  Explain  the  use  of  borax  in  softening  hard  water  ? 

11.  How  are  petrifactions  formed  ? 

12.  In  what  part  of  the  body,  and  in  what  forms,  is  phosphorus 
found  ? 

13.  Why  are  matches  poisonous ?    What  is  the  antidote?    (See 
Physiology,  page  209.) 

14.  Will  the  burning  phosphorus  ignite  the  wood  of  the  match  ? 

*  For  the  more  perfect  examination  of  the  spectra,  a  "  spectroscope  "  is  used. 
This  consists  of  a  tube  with  a  narrow  slit  at  one  end,  which  lets  only  a  single 
ray  <  f  colored  light  fall  upon  the  prism  within,  and  at  the  other  a  small  tele- 
scop  J,  through  which  one  can  look  in  upon  the  prism  and  examine  the  spectrum 
of  any  flame.  (See  Astronomy,  page  285.) 


SPECTRUM    ANALYSIS.  147 

15.  What  philosophical  principle  is  illustrated  in  the  ignition  of 
a  match  by  friction  ? 

16.  How  much  H20  would  be  required  to  dissolve  a  pound  of 
KNO.? 

17.  What  causes  the  bad  odor  after  the  discharge  of  a  gun  ? 

18.  Write  in  parallel  columns  (see  Question  54,  page  96)  the  prop- 
erties of  common  and  of  red  phosphorus. 

19.  What  causes  the  difference  between  fine  and  coarse  salt  ? 

20.  Why  do  the  figures  in  a  glass  paper-weight  look  larger  when 
seen  from  the  top  than  from  the  bottom  ? 

21.  What  is  the  difference  between  water-slacked  and  air-slacked 
lime? 

22.  Why  do  oyster-shells  on  the  grate  of  a  coal-stove  prevent  the 
formation  of  clinkers  ? 

23.  How  is  lime-water  made  from  oyster-shells? 

24.  Why  do  newly-plastered  walls  remain  damp  so  long  ? 

25.  Will  lime  lose  its  beneficial  effect  upon  a  soil  after  frequent 
applications  ? 

26.  What  causes  plaster  of  Paris  to  harden  again  after  being 
moistened  ? 

27.  What  is  the  difference  between  sulphate  and  sulphite  of 
lime? 

28.  What  two  classes  of  rays  are  contained  in  the  magnesium 
light  ? 

29.  What  rare  metals  would  become  useful  in  the  arts,,  if  the 
process  of  manufacture  were  cheapened  ? 

30.  What  is  the  rational  formula  for  calcium  carbonate  ?  Calcium 
sulphite ?    Calcium  sulphate  ? 

31.  Why  is  lime  placed  in  the  bottom  of  a  leach-tub  ? 

32.  Is  saleratus  a  salt  of  K  or  of  Na  ? 

33.  Why  will  Na  burst  into  a  blaze  when  thrown  on  hot  water? 

34.  Why  are  certain  kinds  of  brick  white? 

35.  Illustrate  the  force  of  chemical  affinity. 


INORGANIC     CHEMISTRY. 


THE    USEFUL    METALS, 


IRON. 

Symbol,  Fe Atomic  Weight,  56 Specific  Gravity,  7,8, 

IRON  is  the  symbol  of  civilization.  Its  value  in  the 
arts  can  be  measured  only  by  the  progress  of  the  present 
age.  In  its  adaptations  and  employments  it  has  kept 
pace  with  scientific  discoveries  and  improvements,  so  that 
the  uses  of  iron  may  readily  indicate  the  advancement  of 
a  nation.  It  is  worth  more  to  the  world  than  all  the 
other  metals  combined.  We  could  dispense  with  gold 
and  silver — they  largely  minister  to  luxury  and  refine- 
ment, but  iron  represents  solely  the  honest  industry  of 
labor.  Its  use  is  universal,*  and  it  is  fitted  alike  for  mas- 
sive iron  cables,  and  for  screws  so  tiny  that  they  can  be 
seen  only  by  the  microscope,  appearing  to  the  naked  eye 
like  grains  of  black  sand. 

Its  abundance  everywhere  indicates  how  indispensable 
the  Creator  deemed  it  to  the  education  and  development 


*  "Iron  vessels  cross  the  ocean, 
Iron  engines  give  them  motion, 
Iron  needles  northward  veering, 
Iron  tillers  vessels  steering, 
Iron  pipe  our  gas  delivers, 
Iron  bridges  span  our  rivers, 
Iron  pens  are  used  for  writing, 
Iron  ink  our  thoughts  inditing, 
Iron  stoves  for  cooking  victuals, 
Iron  ovens,  pots,  and  kettles, 
Iron  horses  draw  our  loads, 
Iron  rails  compose  our  roads, 


Iron  anchors  hold  in  sands, 

Iron  bolts  and  rods  and  bands, 

Iron  houses,  iron  walls, 

Iron  cannon,  iron  balls, 

Iron  axes,  knives,  and  chains, 

Iron  augers,  saws,  and  planes, 

Iron  globules  in  our  blood, 

Iron  particles  in  food, 

Iron  lightning-rods  on  spires, 

Iron  telegraphic  wires, 

Iron  hammers,  nails,  and  screws, 

Iron  everything  we  use." 


IRON.  149 

of  man.  There  is  no  "  California  "  of  iron.  Each  nation 
has  its  own  supply.  No  other  material  is  so  enhanced  in 
value  by  labor. 

1  lb.  good  iron  is  worth,  say $  .04 

1  "    bar  steel '. .17 

1"    inch-screws 1.00 

1"    steel  wire 3  to  7.00 

1  "    sewing-needles 14.00 

1  "    fish-hooks 20  to  50.00 

1  "   jewel-screws  for  watches 3,500.00 

1  "    hair-springs  for  American  watches . . .     16,000.00  * 

Source. — Fe  is  rarely  found  native,  i.  e.,  in  the  metallic 
condition.  Meteors,  however,  containing  as  high  as  93 
per  cent,  of  Fe  associated  with  Ni  and  other  metals, 
have  fallen  to  the  earth  from  space.  Fe  in  combina- 
tion with  various  other  substances  is  widely  diffused.  It 
is  found  in  the  ashes  of  plants  and  the  blood  f  of  animals. 
Many  minerals  contain  it  in  considerable  quantities. 
The  ores  from  which  it  is  extracted  are  generally  oxides 
or  carbonates. 

Preparation.  —  Smelting  of  Iron  Ores.  —  Fe  is 
locked  up  with  0  in  an  apparently  useless  stone.  C  is 
the  key  that  is  ready  made  and  left  for  our  use  by  the 
Creator.  The  process  adopted  at  the  mines  is  very  sim- 
ple. A  tall  blast-furnace  is  constructed  of  stone  and 
lined  with  fire-brick.  At  the  top  is  the  door,  and  at  the 
bottom  are  pipes  for  forcing  in  hot  air,  sometimes  twelve 


*  One  pound  (Troy)  of  fine  gold  is  worth  in  standard  coin  $248.063.  All  the 
above  statements  are  based  on  careful  and  actual  valuation. 

t  There  are  only  about  100  grains  of  Fe  in  the  blood  of  a  full-grown  person— 
about  enough  to  make  a  ten-penny  nail — yet  it  gives  energy  and  life  to  the  sys- 
tem. The  metal  is  often  administered  as  a  tonic  in  the  form  of  a  fine  powder,  or 
a  citrate  of  iron,  and  is  a  powerful  remedy. 


150 


INORGANIC     CHEMISTRY. 


thousand  cubic  feet  per  minute,  by  means  of  pistons 
driven  by  steam-power.    The  furnace,  being  filled  with 


Fig.  59. 


A  Blast-Furnace. 

limestone,  coal  and  iron  ore,  in  alternate  layers,  the  fire 
is  ignited.     The  C  *  unites  with  the  0  of  the  ore,  and 

*  A  little  N  sometimes  unites  with  some  C  and  K,  forming  potassium  cyanide, 
or  with  Ti,  if  any  is  present,  making  beautiful  copper-colored  crystals  of  tita- 
nium cyanide. 


IRQ  N. 


151 


Fig.  GO. 


goes  off  as  C02«  The  CaC03  forms  with  the  Si02  and 
other  impurities  a  richly-col- 
ored glassy  slag,  which  rises 
to  the  top.  The  melted  Fe 
runs  to  the  bottom,  and  is 
drawn  off  in  channels  cut  in 
the  sand  on  the  floor  of  the 
furnace.  The  large  main  one 
is  called  the  sow,  and  the 
smaller  lateral  ones  the  pigs, 
and  hence  the  term  pig-iron. 

Varieties  of  Fe. — The  usual 
forms  are  cast,  wrought,  and 
steel,  depending  upon  the  pro- 
portion of  C  which  they  con- 
tain. Cast-iron  has  from  2  to 
5  per  cent.,  steel  from  1  to  2 
per  cent.,  and  wrought-iron  about  J  per  cent. 

1.  Cast  Fe  is  the  form  which  comes  from  the  fur- 
nace.   It  is  brittle,   cannot  be  welded,   and  is  neither 
malleable  nor  ductile.    It  is  an  exception  to  the  law  that 
"  cold  contracts,"  since  at  the  instant  of  solidification  it 
expands,  so  as  to  copy  exactly  erery  line  of  the  mould  into 
which  it  is  poured.     This  fits  it  perfectly  for  castings. 
These  may  be  made  so  soft  as  to  be  easily  turned  and 
filed,  or  so  hard,  by  cooling  in   iron    moulds,*  that  no 
tool  will  affect  them, 

2.  Wrought  or  Malleable  Fe  is  made  by  burning 
the  C  from  cast-iron,  in  a  current  of  highly-heated  air,  in 
what  is  called  a  reyerberatory  furnace.    The  Fe  is  stirred 


flection  of  a  Blast-Fumaee. 


*  These  moulds  are  called  "chills,"  and  the  iron  is  termed  chilled  iron.    It  is 
used  for  burglar-proof  safes. 


152 


INORGANIC     CHEMISTRY. 


Fig.  61. 


constantly,  and  exposed  to  the  heated  air  by  means  of 

long  "  puddling-sticks,"  as 
they  are  termed.  It  is  taken 
out  while  white-hot  and 
beaten  under  a  trip-hammer 
to  force  out  the  slag;  and 
lastly,  pressed  between  groov- 
ed rollers  to  bring  the  parti- 
cles of  Fe  nearer  each  other 

A  Reverberatory  furnace.  and  give  it  a  fibrous   struct- 

ure.*      It  is  now  malleable 

and  ductile,  and  can  be  welded. f  Fe  is  hardened  by 
cooling  rapidly,  and  softened  by  cooling  slowly.  The 
blacksmith  tempers  his  work  by  plunging  the  article  in 
cold  H20. 

3.  Steel  contains  less  C  than  cast,  -and  more  than 
wrought,  iron.  It  is  therefore  made  from  the  former  by 
burning  out  a  part  of  the  C,  and  from  the  latter  by  heat- 
ing in  boxes  of  charcoal,  and  so  adding  C.J  The  value 
of  steel  depends  largely  upon  its  temper.  This  is  deter- 
mined by  heating  the  article  and  then  allowing  it  to  cool. 
The  higher  the  temperature  the  softer  the  steel.  The 


*  This  fibrous  structure  is  so  noticeable  that  if  a  bar  of  the  best  Fe  be  notched 
with  a  chisel  and  then  broken  by  a  steady  pressure,  the  fracture  will  present  a 
stringy  appearance,  like  that  of  a  green  stick.  By  constant  jarring,  however,  Pe 
tends  to  take  a  crystalline  structure,  becoming  rotten  and  brittle,  so  taat  cannon, 
the  axles  of  cars,  etc,  are  condemned  after  a  certain  time,  although  no  flaw  may 
appear. 

t  It  has  been  beaten  into  leaves  so  thin  that  they  have  been  used  for  writing- 
paper— six  hundred  leaves  being  only  half  an  inch  in  thickness— and  has  been 
drawn  into  wire  as  fine  as  a  hair. 

$  Cheap  knives  made  of  soft  iron  are  often  covered  with  a  superficial  coating 
of  steel  in  this  way.  When  we  use  such  knives,  we  soon  wear  through  this 
crust,  and  find  metal  beneath  which  will  take  no  edge.  This  is  termed  case* 
hardening. 


IRON.  153 

workman  decides  this  by  watching  the  color  of  the  oxide 
which  forms  on  the  surface.*  Razors  require  a  straw  yel- 
low ;  table-knives,  a  purple ;  springs  and  swords  a  bright 
blue;  and  saws  a  dark  blue  tint.f — BLOXAM. 

Bessemer9 s  (Process  is  now  extensively  used  for 
making  steel.  Several  tons  of  the  best  pig-iron  are 
melted,  and  poured  into  a  large  crucible  hung  on 
pivots  so  as  to  be  easily  tilted.  Hot  air  driven  in  from 
beneath,  bubbles  up  through  the  liquid  mass,  producing 
an  intense  combustion.  The  roar  of  the  blast,  the  hot, 
white  flakes  of  slag  ever  and  anon  whirled  upward,  the 
long  flame  streaming  out  at  the  top,  variegated  by  tints 
of  different  metals,  and  full  of  sparks  of  scintillating 
iron,  all  show  the  play  of  tremendous  chemical  forces. 
The  operation  lasts  about  twenty  minutes,  when  the  Fe 
is  purified  of  its  C  and  Si.  Enough  spiegel-eisen  (look- 
ing-glass iron),  an  ore  rich  in  C  and  M  n,  is  added  to  con- 
vert it  into  steel,  when  it  is  poured  out  and  cast  into 
ingots.J 

*  The  thin  pellicles  of  iron-rust  on  standing  H2O  produce  a  beautiful  irides- 
cent appearance  in  the  same  way,  the  color  changing  with  the  thickness  of  the 
oxide.  Just  so  a  soap-bubble  exhibits  a  play  of  variegated  colors  according  to 
the  thickness  of  the  film  in  different  parts.  (See  "  Interference  of  Light,"  Philos- 
ophy, page  209.) 

t  These  colors  are  removed  in  the  subsequent  processes  of  grinding  and 
polishing,  but  they  may  be  seen  in  a  handful  of  old  watch-springs,  to  be  obtained 
of  any  jeweller. 

t  In  1760,  there  lived  at  Attercliffe,  near  Sheffield,  a  watchmaker  named 
Huntsman.  He  became  dissatisfied  with  the  watch-springs  in  use,  and  set  him- 
self to  the  task  of  making  them  homogeneous.  "If,"  thought  he,  "  I  can  melt  a 
piece  of  st-eel  and  cast  it  into  an  ingot,  its  composition  should  be  the  same 
throughout."  He  succeeded.  His  steel  became  famous,  and  Huntsman's  ingots 
were  in  universal  demand.  He  did  not  call  them  cast-steel.  That  was  his 
secret.  The  process  was  wrapped  in  mystery  by  every  means.  The  most  faith- 
ful men  were  hired.  The  work  was  divided,  large  wages  paid,  and  stringent 
oaths  taken.  One  midwinter  night,  as  the  tall  chimneys  of  the  Atterclifie  steel- 
works belched  forth  their  smoke,  a  belated  traveler  knocked  at  the  gate.  It  was 
bitter  cold;  the  snow  fell  fast;  and  the  wind  howled  across  the  moor.  The 
stranger,  apparently  a  common  farm-laborer  seeking  shelter  from  the  storm, 


154,  INORGANIC     CHEMISTRY. 

Compounds. — 1.  Black  or  Magnetic  Oxide  (Fe304)  is 
found  in  the  loadstone,  Swedish  iron-ore,  scales  which  fly 
off  in  forging  iron,  and  in  mines  in  various  parts  of  the 
United  States.  It  is  the  richest  of  the  ores  and  contains 
as  high  as  72  per  cent,  of  the  metal.  2.  Red  Oxide 
of  Iron,  sesquioxide  (ferric  oxide,  Fe203),  is  seen  in  red 
iron-ore,  in  the  beautiful  radiated  and  fibrous  speci- 
mens of  hematite,*  specular  f  iron,  red  ochre  and  chalk, 
bricks  and  pottery-ware.  The  sesquioxide,  combining 
with  H20,  forms — 3.  Hydrated  Sesquioxide  of  Iron  (fer- 
ric hydrate,  Fe203,3H20).  This  has  a  brown  or  yellow 
color,  which  changes  to  red  by  heat  when  the  water  is 
expelled,  as  in  the  burning  of  brick,  pottery-ware,  J  etc. 
These  oxides  generally  give  the  brown,  yellow,  or  red 
tints  seen  in  sand,  gravel,  etc.  The  ferric  oxide  and 
hydrate  are  remarkable  for  the  facility  with  which  they 
absorb  0  from  the  air,  and  impart  it  to  other  bodies. 
This  is  familiar  in  the  rusting  of  nails  in  clap-boards, 
hinges  in  gate-posts,  hooks  in  ropes,  etc,  etc. 

Iron  Carbonate)  FeC03,  is  found  as  spathic  §  and 


awakened  no  suspicion.  The  foreman,  scanning  him  closely,  at  last  granted  his 
request  and  let  him  in.  Feigning  to  be  worn-out  with  cold  and  fatigue,  the  poor 
fellow  sank  upon  the  floor  and  was  soon  seemingly  fast  asleep.  That,  however, 
was  far  from  his  intention.  Through  cautiously  opened  eyes,  he  caught  glimpses 
of  the  mysterious  process.  He  saw  workmen  cut  bars  of  steel  into  bits,  place 
them  in  crucibles,  which  were  then  thrust  into  the  furnaces.  The  fires  were  urged 
to  their  utmost  intensity  until  the  steel  melted.  The  workmen,  clothed  in  rags, 
wet  to  protect  them  from  the  tremendous  heat,  drew  forth  the  glowing  crucibles 
and  poured  their  contents  into  moulds.  Huntsman's  factory  had  nothing  more 
to  disclose.  The  secret  of  cast-steel  was  stolen. 

*  Hamatites,  blood-like,  from  the  red  color  of  its  powder. 

t  Speculum,  a  mirror,  from  the  brilliant  lustre  of  its  steel-gray  crystals  and 
mica-like  scales  in  micaceous  iron-ore. 

$  Clay,  containing  ferrous  oxide  (FeO),  becomes  red  by  its  conversion  into 
ferric  oxide. 

§  Spath,  spar,  as  some  specimens  consist  of  transparent,  shiny  crystals,  hav- 
ing the  same  form  as  calcareous  spar  (calcium  carbonate). 


IRON.  155 

clay  ironstone,  and  often  contains  some  manganese,* 
which  fits  it  for  the  manufacture  of  certain  kinds  of 
steel,  whence  it  is  termed  steel-ore.  In  chalybeate  springs, 
the  free  C02  in  the  water  holds  the  FeC03  in  solution. 
On  coming  to  the  air,  the  C02  escapes,  and  the  Fe,  ab- 
sorbing 0,  is  deposited  as  hydrated  ferric  oxide,  forming 
the  ochry  deposit  so  common  around  such  springs. 

Iron  bisulphide  (FeS2),  Iron  Pyrites,  FooVs  Gold 
— so  called,  because  it  is  often  mistaken  by  ignorant  per- 
sons for  Au.  It  occurs  in  cubical  crystals  and  bright 
shiny  scales.  It  can  be  easily  tested  by  roasting  on  a  hot 
shovel,  when  we  shall  catch  the  well-known  odor  of  the 
SO  2.  FeS2  is  used  as  a  source  of  S,  and  also  in  the 
manufacture  of  H2S04. 

Ferrous  Sulphate  (FeS04,7H20),  Green  Vitriol, 
Copperas,  is  made  by  the  action  of  H2S04  on  Fe,  and,  at 
Stafford,  Connecticut,  from  FeS2,  by  exposure  to  air  and 
moisture.  It  is  used  in  dyeing,  making  ink,  and  in  pho- 
tography. 

*  Manganese  is  a  hard,  brittle  metal,  resembling  cast-iron  in  its  color  and 
texture.  It  takes  a  beautiftal  polish.  Its  binoxide,  the  black  oxide  of  manganese, 
is  used  in  the  manufacture  of  O,  Cl,  etc.  By  fusing  MnOa,  KC1OS,  and  KHO,  a 
dark,  green  mass  is  obtained  called  "chameleon  mineral."  It  contains  potas- 
sium manganate.  If  a  piece  of  this  be  placed  in  HaO,  the  solution  will  undergo 
a  beautiful  change  from  green,  through  various  shades,  to  purple.  This  is 
owing  to  the  gradual  formation  of  permanganic  acid.  The  change  may  be  pro- 
duced instantaneously  by  a  drop  of  HaSO4.  Potassium  permanganate  is  remark- 
able for  the  facility  with  which  it  parts  with  its  O,  and  thereby  loses  its  color. 
It  is  used  extensively  as  a  disinfectant,  and  as  a  test  of  the  presence  of  organic 
matter.  (See  page  60.) 


156 


INORGANIC     CHEMISTRY. 


ZINC. 

Symbol,  In Atomic  Weight,  65 Specific  Gravity,  7,15. 

Fusing  Point,  773°  F, 

Source. — Zn,  or  "  spelter/'  as  it  is  called  in  commerce, 
is  found  as  ZnO,  or  red  oxide,  in  New  Jersey,  and  as  ZnS, 
or  zinc  blende,  in  many  places. 

Preparation.— ZnO  is  smelted  on 
mg'  6®'  the  same  principle  as  iron  ore,  by 

heating  with  C.  The  reaction  is 
as  follows:  ZnO  +  C  =  Zn  +  CO. 
Both  these  products  distil,  the 
Zn  vapor  being  condensed  while 
the  CO  gas  escapes. 

Properties . — Zn  is  ordinarily 
brittle,  but  when  heated  to  200° 
or  300°  R,  it  becomes  malleable, 
and  can  be  rolled  out  into  the  sheet 
Zn  in  common  use.  It  burns  in 
the  air  with  a  magnificent  green 
light,  forming  flakes  of  ZnO,  sometimes  called  "Philoso- 
pher's Wool."  *  When  exposed  to  the  air  Zn  soon  oxi- 
dizes, and  the  thin  film  of  white  oxide  formed  over  the 
surface  protects  it  from  further  change. 

Uses. — Its  economic  uses  are  familiar.  Sheet  Fe 
dipped  in  melted  Znm forms  what  is  termed  galvanized 
iron.  Water-pipes  made  of  this  material  are  as  unsafe 
as  lead  (see  p.  160)  until  the  Zn  is  entirely  corroded. 


Roasting  Zinc  Ore. 


*  Example :  On  a  red-hot  ladle,  sprinkle  some  powdered  saltpetre  and  Zn 
filings.  The  KN08  will  furnish  0,  and  the  metal  will  burn  with  great  bril- 
liancy. 


TIN.  157 

The  oxide  and  carbonate  of  zinc  are  rapidly  formed,  and 
these  poisonous  salts  remain  in  the  H20.  There  is  the 
same  objection  to  metallic-lined  ice-pitchers.  Galvanic 
action  bet<eeen  the  metals  promotes  corrosion.  H20 
standing  in  reservoirs  lined  with  Zn  should  not  be  used 
for  drinking  purposes.  In  the  case  of  zinc-covered  roofs 
the  rain-water  contains  zinc  oxide.* 

Compounds. — Zinc  Oxide,  ZnO,  is  sold  as  zinc- 
white,  and  is  valued  as  a  paint,  since  it  does  not  blacken 
by  H2S  like  white-lead;  but  it  is  quite  as  hurtful  to  the 
painter.  Zinc  sulphate  (ZnS04),  -white  vitriol,  is  used  in 
medicine. 


TIN. 

Symbol,  Sn Atomic  Weight,  118 Specific  Gravity,  7,2, 

Fusing  Point,  442°  F, 

Source.— Sn,  though  one  of  the  metals  longest  known 
to  man,  is  found  in  but  few  localities.  It  is  reduced  from 
its  binoxide  by  the  action  of  C. 

Properties. — It  is  soft  and  not  very  ductile,  but  is  quite 
malleable,  so  that  tinfoil  is  not  more  than  T^^  of  an  inch 
in  thickness.  When  quickly  bent,  it  utters  a  shrill  sound, 
called  the  "  tin  cry,"  caused  by  the  crystals  moving  upon 
each  other.  Sn  does  not  oxidize  at  ordinary  temper- 
atures. Its  tendency  to  crystallize  is  remarkable,  f 

• 

*  When  they  were  first  introduced  in  Boston  the  washerwomen  complained 
that  the  rain-water  was  hard,  decomposed  the  soap,  and  made  their  hands 
crack. 

t  Example :  Heat  a  piece  of  Sn  till  the  coating  begins  to  melt ;  then  cool 
quickly  in  H3O  and  clean  in  dilute  aqua-regia.  The  surface  will  be  found  cov- 
ered with  beautiful  crystals  of  the  metaL 


158  INORGANIC     CHEMISTRY. 

Uses. — Common  sheet-tin  is  formed  by  dipping  sheet- 
iron  in  melted  Sn,  which  produces  an  artificial  coating 
of  the  latter  metal.  If  we  leave  H  20  in  a  tin  dish,  the 
yellow  spots  soon  betray  the  presence  of  Fe.  Pins  made 
of  brass  wire  are  boiled  with  granulated  tin,  cream  of 
tartar,  and  H20,  which  give  a  bright  white  surface  to 
the  metal.* 


COPPER. 

Symbol,  Cu Atomic  Weight,  63.5 Specific  Gravity,  8,9, 

Fusing  Point,  1994°  F, 

Source. — Cu  is  found  native  near  Lake  Superior,  fre- 
quently in  masses  of  great  size.  In  these  mines  stone 
hammers  have  been  discovered,  the  tools  of  a  people  older 
than  the  Indians,  who  probably  occupied  this  continent, 
and  worked  the  mines.  In  the  western  mounds,  also, 
copper  instruments  are  found.  The  sulphide,  copper 
pyrites,  is  a  well-known  ore.  Malachite  (CuC03,CuO, H  20), 
the  green  carbonate,  admits  of  a  high  polish,  and  is  made 
into  ornaments  of  exquisite  beauty. 

Properties. — Cu  is  ductile,  malleable,  and  an  excellent 
conductor  of  heat  and  electricity.  Its  vapor  gives  a  char- 
acteristic and  beautiful  green  color  to  flame.  It  is  har- 
dened by  hammering,  and  softened  by  heating  and  plung- 
ing into  cold  H20.f  HN03  is  the  solvent  of  Cu.  Its  test 

*  The  pins  are  stuck  in  papers,  as  we  see  them,  by  machinery  which  picks 
them  up  out  of  a  miscellaneous  pile,  counts  them,  and  inserts  them  in  the  paper, 
ready  for  the  market.  The  first  part  of  the  process  is  performed  by  a  sort  of 
coarse  comb,  which  is  thrust  into  the  heap,  and  gathers,  up  a  pin  in  each  of  the 
spaces  between  the  teeth. 

t  The  reverse  of  Pe,  which  fact  ruins  any  theory  we  might  form  as  to  the  cause 
In  either  case. 


LEAD.  .  159 

is  H3N,  forming  in  a  solution  an  azure-blue  precipitate, 
which  dissolves  in  an  excess  of  the  reagent. 

Compounds. — Copper  Acetate,  Verdigris,*  is  pro- 
duced when  we  soak  pickles  in  brass  or  copper  kettles ; 
the  green  color  which  results  is  caused  by  this  salt — a 
deadly  poison.  Preserved  fruits,  etc.,  should  never  stand 
in  such  vessels,  as  the  vegetable  acids  dissolve  Cu  readily. 

Copper  Oxide,  CuO,  is  the  black  coating  which 
collects  on  copper  or  brass  kettles,  and  is  very  poisonous. 
It  dissolves  readily  in  fats  and  oils.  Such  utensils  should 
therefore  be  used  only  when  perfectly  bright,  and  never 
with  fruits,  sweetmeats,  jellies,  pickles,  etc. 

Copper  Su2p?iate  (CuS04,5H20),  Blue  Vitriol,  is 
much  used  in  dyeing,  calico  printing,  and  galvanic  bat- 
teries. 


LEAD. 

Symbol,  Pb Atomic  Weight,  207 Specific  Gravity,  11,36, 

Fusing  Point,  620°  F. 

Source. — The  most  common  ore  of  Pb  is  galena,  PbS, 
which  is  reduced  by  roasting  in  a  reverberatory  furnace. 
The  S  burns  and  leaves  the  metal. 

Properties. — Pb  is  malleable,  but  contracts  as  it  solidi- 
fies ;  so  it  cannot  be  used  for  castings.  It  is  poisonous, 
though  not  immediately,  as  "  bullets  have  been  swallowed, 
and  then  thrown  off  without  any  harm  except  the  fright." 
Its  effects  seem  to  accumulate  in  the  system,  and  finally 

*  The  term  verdigris  is  sometimes  incorrectly  applied  to  the  green  coating  of 
carbonate,  which  gathers  upon  brass  or  copper  in  a  damp  atmosphere. 


160  INORGANIC     CHEMISTRY. 

to  manifest  themselves  in  some  disease.  Persons  who 
work  in  lead,  as  painters  and  plumbers,  after  a  time  suffer 
with  colics,  paralysis,  etc. 

Uses. — Pb  is  much  used  for  water-pipes,  and  is  the 
most  convenient  of  any  metal  for  that  purpose.  Pure 
H20  passing  through  the  pipe  will  not  corrode  the  Pb, 
but  the  0  of  the  air  it  contains  forms  an  oxide  of 
lead  which  dissolves  in  the  H20,  leaving  a  fresh  surface 
for  oxidation.  If  there  are  any  sulphates  or  carbonates 
in  the  H20,  they  will  form  a  coating  over  the  Pb,  and 
protect  it  from  further  corrosion ;  and  as  carbonate  of 
lime  is  common  in  hard  water,  that  is  generally  safe.  If, 
when  we  examine  a  lead  pipe  that  is  in  constant  use,  we 
find  it  covered  with  a  white  film,  it  is  a  good  sign ;  but  if 
it  is  bright,  there  is  cause  for  alarm.  Still,  however  much 
may  be  said  upon  the  danger,  people  will  use  lead  pipes, 
and  the  following  precautions  should  be  observed :  Al- 
ways let  the  water  run  long  enough  in  the  morning  before 
using,  to  remove  all  which  has  remained  in  the  water-pipes 
during  the  night ;  and  when  the  H  20  is  let  on  again  after 
it  has  been  shut  off  for  a  while,  leave  the  faucet  open 
until  the  pipe  is  thoroughly  washed. 

The  Test  of  Pb  is  H2S,  forming  lead  sulphide,  PbS. 
The  following  is  an  interesting  illustration:  Thicken 
a  solution  of  lead  acetate  with  a  little  gum-arabic,  so  as 
not  to  flow  too  readily  from  the  pen,  and  then  make  any 
sketch  which  your  fancy  may  suggest.  This,  when  dry, 
will  be  invisible.  When  it  is  to  be  used,  dampen  the 
paper  slightly  on  the  wrong  side,  and  then  direct 
against  it  a  jet  of  H2S.  The  picture  will  at  once  blacken 
into  distinctness. 

Compounds. — Z,ead   Oxide,   PbO,  the  well-known 


LEAD. 


161 


Fig.  6S. 


litharge,  is  formed  by  heating  Pb  in  a  current  of  air.* 
It  is  used  in  glass-making,  in  paints,  and  in  glazing 
earthenware. 

Lead  ^Dioxide,  Pb02,  is  formed  by  oxidizing  PbO. 
A  mixture  of  the  two,  called  minium  or  red-lead,  is  used 
for  coloring  sealing-wax  red,  and  as  a  paint. 

Lead  Carbonate,  (PbC03),  White-Lead.— This  salt, 
is  made  in  large  quantities  in  the  following  manner: 
Thousands  of  earthen  pots  fitted  with  covers 
and  containing  weak  vinegar  (acetic  acid) 
and  a  small  roll  of  Pb,  are  arranged  in  im- 
mense piles,  and  then  covered  with  tan-bark. 
The  acetic  acid  combines  with  the  Pb,  but 
the  CO 2  formed  by  the  decomposing  tan- 
bark  creeps  in  under  the  cover,  driving  off 
the  acetic  acid,  and  forming  lead  carbonate. 
The  acetic  acid,  thus  dispossessed,  attacks 
another  portion  of  the  Pb,  but  is  robbed 
again ;  and  so  the  process  goes  on,  until  at 
last  the  Pb  is  exhausted.    White-lead  is  largely  adulter- 
ated with  heavy  spar,  gypsum,  etc. 

Lead  Acetate,  Sugar  of  Lead,  has  a 
sweet,  pleasant  taste,  but  is  a  virulent  poison. 
Its  antidote  is  Epsom  salt,  which  forms  an 
insoluble  lead  sulphate.  H20  dissolves  sugar 
of  lead  readily.  If  a  piece  of  Zn,  cut  in  small 
strips,  be  suspended  in  a  bottle  filled  with  a 
solution  of  lead  acetate,  the  Pb  will  be  depos- 
ited upon  it  by  voltaic  action  in  beautiful 
metallic  spangles,  forming  the  "  lead-tree." 


A.— An 

pot. 

L.-A  coil  of  lead. 
V.— A  solution  of 


Fig. 


*  Example :  Heat  a  bit  of  lead  upon  charcoal  in  the  oxidizing  flame  of  the 
blow-pipe.  A  film  of  the  suboxide  forms  first,  then  a  yellow  crust  of  the  pro- 
toxide. 


162  INORGANIC     CHEMISTRY. 

THE   NOBLE   METALS, 

Au,  Ag,  Pt,  Hg,   Pd,  Ir,  Os,  Ru,  and  Ro, 


GOLD. 

Symbol,  Au Atomic  Weight,  197 Specific  Gravity,  19,34, 

Fusing  Point,  about  2015°  F, 

Sources. — Au  is  found  sometimes  in  masses  called  nug- 
gets, but  generally  in  scattered  grains,  or  scales.  As  the 
rocks  in  which  it  occurs  disintegrate  by  the  action  of  the 
elements  and  form  soil,  the  Au  is  gradually  washed  into 
the  valleys  below,  and  thence  into  the  streams  and  rivers, 
where,  owing  to  its  specific  gravity,  it  settles  and  collects 
in  the  mud  and  gravel  of  their  beds.* 

Preparation. — As  the  metal  is  thus  found  native,  the 
process  is  purely  mechanical,  and  consists  simply  in  wash- 
ing out  the  dirt  and  gravel  in  wash-pans,  rockers,  sluices,  f 
etc.,  at  the  bottom  of  which  the  Au  accumulates.  In  the 
quartz-mills,  the  rock  is  thrown  into  troughs  of  water, 
where,  by  heavy  stamps,  the  ore  is  crushed  to  powder. 

*  In  California,  Au  is  found  in  the  detritus  (small  particles  of  rock  -worn  off  by 
attrition)  of  granite  and  quartz.  It  occurs  in  the  gravel  of  hills  from  the  surface 
to  the  "bed-rock,"  sometimes  a  depth  of  300  to  500  feet ;  in  the  alluvial  soil  of 
the  plains,  and  even  in  vegetable  loam  among  the  roots  of  grass. 

t  Sluices  are  generally  used  in  California.  These  are  gently  inclined  troughs, 
sometimes  extending  for  miles.  Across  the  bottom  are  fastened  low  wooden 
bars,  called  riffles,  above  which  quicksilver  is  placed.  The  dirt  is  shovelled*  into 
these  sluices,  or  the  auriferous  hills  are  cut  down,  dissolved,  and  washed  through 
them  by  powerful  streams  of  water,  which  are  constantly  running.  The  HaO 
floats  off  the  debris,  while  the  Hg  catches  the  gold. 


GOLD.  163 

As  the  thin  liquid  mud  thus  formed  splashes  up  on  either 
side,  it  runs  over  broad,  metallic  tables  covered  with  Hg; 
or  is  washed  through  a  fine  wire-screen,  and  carried  to 
the  "  amalgamating-pans "  by  a  little  stream  of  water. 
The  Hg  unites  with  the  particles  of  Au  and  forms  with 
them  an  amalgam  (a  compound  of  mercury  and  a  metal). 
Au  is  easily  separated  from  Hg  by  distillation,*  and  the 
latter  collected  to  be  used  again. 

Quartation. — Au  is  commonly  found  alloyed  with  Ag. 
The  Ag  is  then  dissolved  out  by  HN03.  There  must  be 
at  least  three  parts  of  Ag  to  one  of  Au,  else  the  gold  will 
protect  the  silver  from  the  action  of  the  acid.  If  there 
is  not  so  much,  some  is  fused  with  the  alloy. f 

Properties. — Pure  Au  is  nearly  as  soft  as  Pb.  It  is  ex- 
tremely malleable  J  and  ductile.  Its  solvent  is  aqua-regia. 
It  does  not  oxidize  at  any  temperature,  and  on  account 
of  its  indestructibility,  it  was  anciently  called  the  king  of 
the  metals. 

*  The  larger  part  of  the  Hg  is  separated  from  the  amalgam  by  pressure  in  can- 
vas or  buckskin  bags,  the  liquid  Hg  escaping  through  the  pores,  while  the  amal- 
gam is  left  quite  dry.  The  latter  is  then  u  retorted  "  for  distillation. 

t  "  In  works  for  the  refining  of  gold  and  silver,  the  processes  can  be  conducted 
economically  only  when  great  care  is  taken  to  avoid  the  loss  of  any  particles  of 
the  precious  metals.  Thus  all  the  old  crucibles  are  ground  and  treated  with 
mercury,  and  after  as  much  gold  and  silver  as  possible  have  been  extracted,  the 
residues  are  sold  to  the  sweep-washers,  who  extract  a  little  more  by  melting  with 
lead.  The  very  dust  off  the  floors  is  collected  and  treated  in  a  similar  way."— 
BLOXAM. 

$  For  a  description  of  the  process  of  making  gold-leaf,  see  Philosophy,  p.  29. 
"  When  one  of  these  leaves  is  held  up  to  the  light,  it  exhibits  a  beautiful  green 
color,  and  if  it  be  rendered  still  thinner,  either  by  beating,  or  by  floating  it  upon 
a  very  weak  solution  of  potassium  cyanide,  which  slowly  dissolves  it,  it  trans- 
mits, when  taken  upon  a  glass  plate  and  held  up  to  the  light,  a  blue,  violet,  or 
red  light,  in  proportion  as  its  thickness  diminishes.  Even  when  it  is  so  trans- 
parent that  one  may  read  through  it,  the  yellow  color  and  lustre  of  the  gold  are 
still  visible  by  reflected  light.  These  varying  colors  of  finely-divided  gold  are 
turned  to  account  in  the  coloring  of  glass  and  in  painting  on  porcelain." — MILLER. 


164 


INORGANIC     CHEMISTRY. 


SILVER. 

Symbol,  Ag Atomic  Weight,  108 Specific  Gravity,  10,5. 

Fusing  Point,  1873°  F, 

Sources. — Silver  is  found  throughout  the  West  in  a 
great  variety  of  forms — most  commonly,  however,  com- 
bined with  S,  as  UacJc  sulphide,  Ag2S;  with  Cl,  forming 

Fig.  65. 


Separation  of  Pb/nwi  Ag.    (See  Sloxam's  Metals.) 

horn-silver,  AgCl;   with  S  and  As  or  Sb,  making  ruby- 
silver,  and  also  associated  with  Pb  in  ordinary  galena. 


SIL  VER.  165 

Preparation. — 1st.  The  sulphide  is  refined  as  follows : 
The  ore  is  crushed  into  fine  powder  and  then  roasted 
with  common  salt.  The  Cl  of  the  salt  unites  with  the 
Ag,  forming  silver  chloride.  This  is  next  put  into  a 
revolving  cylinder  with  H20,  Hg,  and  iron  scraps.  The 
Fe  removes  the  Cl  from  the  silver,  when  the  Hg  takes 
it  up,  thus  forming  an  amalgam  of  Hg  and  Ag.  From 
this  the  Ag  is  easily  obtained,  as  in  gold-washing.*  3d. 
From  horn-silver,  AgCl,  the  process  is  like  the  latter  part 
of  that  just  described.  3d.  From  lead  the  Ag  can  be  pro- 
fitably obtained  when  there  are  only  two  or  three  ounces 
in  a  ton.  The  alloy  of  the  two  metals  is  melted  and  then 
slowly  cooled.  Pb  solidifies  much  sooner  than  Ag,  and 
by  skimming  out  the  crystals  of  Pb  as  fast  as  formed, 
it  may  be  almost  entirely  separated.  (See  Fig.  65.) 

CupeUation.  —  A  cupel   (cupella,  a  Mff  66 

small  cup)  is  a  shallow  vessel,  made  of 
bone-ashes.  In  this  the  Ag,  debased  with 
Pb  and  other  impurities,  is  exposed  to  a 
red  heat,  so  as  to  melt  the  metals,  while  a 
current  of  hot  air  plays  upon  the  surface. 
The  Pb  oxidizes  to  PbO,  and  is  absorbed  by  the  porous 
cupel.  The  mass  appears  soiled  and  tarnished,  but  the 
refiner  keeps  his  eye  upon  it  as  the  process  continues, 
watching  eagerly,  until  at  last  there  is  a  brilliant  play  of 
colors — he  catches  his  own  image-  in  the  perfect  metallic 
mirror,  and  the  little  "button"  of  pure  silver  lies  gleam- 

*  The  process  of  reducing  silver  ores  at  the  West  is  unlike  the  German  method 
given  above,  and  varies  in  different  localities.  One  plan  is  as  follows:  The 
powdered  and  roasted  AgaS  is  placed  with  Hg  in  iron  pans,  five  feet  in  diameter 
and  two  feet  deep.  Here  it  is  kept  heated  by  steam  to  180"  and  agitated  by 
revolving  stirrers.  The  chloride  is  not  roasted,  but  is  simply  powdered,  and 
then  worked  in  the  pans  for  an  hour  with  NaCl  before  adding  the  Hg.— STE- 
VENSON. 


166 


INORGANIC     CHEMISTRY. 


ing  at  the  bottom.*     This  must  now  be  immediately 
removed,  or  it  will  oxidize  and  waste. f 


Fig.  67. 


Cupds  in  Furnace. 

Properties. — Ag  is  the  whitest  of  the  metals.  It  is 
malleable  and  ductile.  It  expands  at  the  moment  of 
solidification,  and,  therefore,  can  be  cast.  It  has  a  power- 


*  See  Malachi  iii.  3. 

t  During  the  cooling  of  the  cake  of  Ag,  some  very  remarkable  phenomena  are 
observed.  When  a  thin  crust  of  metal  has  formed  upon  the  surface,  the  Ag  be- 
neath it  assumes  the  appearance  of  boiling,  and  the  crust  is  forced  up  into  hollow 
cones  about  an  inch  high,  through  which  the  melted  Ag  is  thrown  out  with  ex- 
plosive violence,  some  of  it  being  splashed  against  the  arch  of  the  furnace,  and 
some  solidifying  into  most  fantastic  tree-like  forms  several  inches  in  height. 
This  behavior  of  Ag  has  been  shown  to  be  due  to  its  property  of  mechanically 
absorbing  O,  at  a  temperature  above  its  melting-point,  which  it  gives  off  as  it  ap- 
proaches the  point  of  solidiflcation,-the  escaping  gas  forcing  up  the  crust  of  solid 
Ag  formed  upon  the  surfece. 


SIL  VE  R.  167 

ful  attraction  for  S,  forming  silver  sulphide.*  Silver 
,  spoons  and  door-knobs  are  tarnished  by  the  minute  quan- 
tities of  H2S  present  in  the  air.f  The  best  solvent  of  Ag 
is  HN03.  The  test  of  Ag  in  solution  is  HC1,  which  forms 
a  cloudy  precipitate  of  silver  chloride.  A  solution  of  silver 
coin  is  blue,  from  the  Cu  it  contains.  Standard  silver  is 
whitened  by  being  heated  until  the  0  of  the  air  has  con- 
verted a  little  of  the  Cu  on  the  outside  into  CuO,  which  is 
dissolved  by  immersing  in  dilute  H2S04  or  H3N.  The 
film  of  nearly  pure  Ag  which  then  remains  at  the  surface 
exhibits  a  want  of  lustre  and  is  called  dead  or  frosted  sil- 
ver. It  is  brightened  by  burnishing. 

Compounds,  —  Silver  Nitrate,  AgN03,  is  sold  in 
small,  round  sticks  as  lunar  caustic,  used  as  a  cautery.  It 
stains  the  skin  and  all  organic  matter  black,  especially 
when  exposed  to  the  light,  owing  to  the  formation  of 
silver  oxide,  Ag204  Hair-dyes  and  indelible  inks  con- 
tain AgN03.  It  is  also  the  basis  of  photography  (light- 
drawing)  and  daguerreotyping,§  which  are  both  founded 


*  The  perspiration  from  our  bodies  contains  more  or  less  S,  and  this,  as  it 
passes  through  our  pockets,  combines  with  any  silver  we  may  chance  to  have 
there. 

t  Those  who  have  visited  sulphur  springs  know  the  propriety  of  carefully  pro- 
tecting their  watches,  and  of  never  wearing  gold  ornaments  to  the  hot  baths. 
Ag2S  is  very  easily  dissolved  by  a  little  dilute  ammonia  (1  part  of  HNS  to  20  of 
HaO),  which  is  therefore  used  for  cleaning  silver  door-knobs.—  Oxidized  silver, 
as  it  is  erroneously  called,  is  made  by  immersing  articles  of  silver  in  a  solution 
obtained  by  boiling  sulphur  with  potash,  when  the  metal  becomes  coated  with  a 
thin  film  of  sulphuret  of  silver. — BLOXAM. 

%  A  very  pretty  experiment,  illustrating  the  formation  of  this  oxide,  is  per- 
formed by  dropping  into  a  test-tube  of  H2O  a  few  drops  of  silver  nitrate  in  solu- 
tion, and  then  adding  potash,  when  a  copious  precipitate  of  the  brown  hydrate  of 
Ag2O'will  fill  the  tube.  Now  put  in  a  little  H3N,  which  will  instantly  dissolve 
the  silver  oxide,  and  leave  the  liquid  as  clear  and  sparkling  as  spring-water.— 
The  stain  of  silver  nitrate  may  be  removed  by  a  strong  solution  of  potassium 
iodide  or  the  poisonous  potassium  cyanide. 

§  The  daguerreotype  is  named  from  M.  Daguerre,  the  discoverer,  who  received 
a  pension  of  6,000  francs  per  year  from  the  French  government.  A  plate  of  Cn, 


168  INORGANIC     CHE  MIS  TR  Y. 

upon  essentially  the  same  principles.  The  general  out- 
lines of  the  photographic  process  are  as  follows:  1. 
Iodized  collodion*  is  poured  upon  a  clean  glass  plate, 
which,  on  evaporation,  it  covers  with  a  transparent  film. 
2.  The  plate  is  put  in  the  "nitrate  of  silver  bath,"  f  where 
the  salt^  of  silver  is  absorbed  by  the  collodion  film  and 
changed  to  brom-iodide  of  silver.  The  plate  is  now  ready 
for  the  picture.  After  the  sitting,  the  plate  is  taken, 
carefully  protected  from  the  light,  to  the  operator's  room. 
Here  the  picture  is,  3,  developed  by  a  solution  of  ferrous 
sulphate  (protosulphate  of  iron)  or  pyrogallic  acid  (see  p. 
212) :  at  the  right  stage  the  liquid  is  washed  off,  and  the 
operation  checked.  4.  It  is  fixed  with  a  solution  of  so- 
dium hyposulphite,  which  dissolves  the  unaltered  brom- 
iodide  of  silver.  5.  It  is  washed,  dried,  and  coated  with 
amber  varnish  to  preserve  the  film  from  accidental  injury. 
The  "  negative "  is  now  completed,  and  is  a  correct  like- 

plated  on  one  side  with  Ag,  is  exposed  to  the  vapor  of  I  and  Br  until  a  compound 
of  brom-iodide  of  silver  is  formed  upon  the  surface.  This  is  extremely  sensitive 
to  the  light,  hence  the  process  is  always  conducted  in  a  dark  closet.  The  plate  is 
then  quickly  carried,  carefully  covered,  to  the  camera,  and  placed  in  the  focus, 
where  the  rays  of  light  from  the  person  whose  "picture  is  being  taken"  fall 
directly  upon  it  These  rays  decompose  the  brom-iodide  of  silver.  The  amount  of 
this  change  is  directly  proportional  to  the  number  of  rays  that  are  reflected  from 
different  parts  of  the  person  to  form  the  image  in  the  camera.  A  white  garment 
reflects  all  the  light  that  falls  upon  it,  so  the  corresponding  part  of  the  plate  will 
be  very  much  changed.  A  black  garment  reflects  no  light,  so  that  part  will  not 
be  changed  at  all.  The  different  colors  and  shades  reflect  varying  proportions  of 
light,  and  so  influence  the  plate  correspondingly.  When  the  plate  is  taken  out 
of  the  camera,  it  is  carefully  covered  again  and  carried  quickly  into  the  dark 
closet.  No  change  can  be  detected  by  the  eye ;  but  on  exposure  to  the  vapor 
of  Hg,  wherever  the  Ag  has  been  freed,  the  Hg  will  combine  with  it,  forming  a 
whitish  amalgam,  but  it  has  no  effect  on  the  rest  of  the  plate.  The  picture  thus 
treated  comes  forth  nearly  perfect  in  its  lights  and  shades.  The  undecomposed 
brom-iodide  of  silver  is  removed  by  a  solution  of  sodium  hyposulphite.  A  solu- 
tion of  gold  chloride  and  sodium  hyposulphite  is  then  poured  upon  the  plate  and 
warmed.  This  golden  varnish  finishes  the  picture. 

*  Iodized  collodion  is  composed  of  gun-cotton  dissolved  in  alcohol  and  ether, 
to  which  are  added  ammonium  iodide  and  cadmium  bromide,  or  similar  salts. 

t  The  nitrate  of  silver  bath  contains  nitrate  of  silver  and  iodide  of  silver  in 
solution,  and  is  acidulated  with  nitric  acid. 


PLATINUM.  169 

ness,  only  the  lights  and  shades  are  reversed.  From  this 
the  pictures  are,  1,  "printed"  by  placing  the  negative 
upon  a  sheet  of  prepared  paper,*  and  exposing  it  to  the 
sun's  rays.  When  the  colors  are  sufficiently  deepened, 
the  picture  is,  2,  toned  in  the  "  toning-bath,"  which  con- 
tains a  little  "  bicarbonate  of  soda "  and  a  minute  quan- 
tity of  gold  chloride ;  3,  fixed,  by  sodium  hyposulphite 
which  dissolves  the  unaltered  AgCl ;  4,  thoroughly 
washed  in  water  frequently  renewed ;  and,  lastly,  dried 
and  mounted  on  card-board.  The  thoroughness  of  the 
third  and  fourth  processes  has  much  to  do  with  the  per- 
manence of  the  picture.  If  any  of  the  chloride  or  the 
compound  formed  by  the  hyposulphite  be  left,  it  will 
cause  fading  or  discoloration. 


PLATINUM. 

Symbol,  Pt. . .  .Atomic  Weight,  197. ..  .Specific  Gravity,  21,53, 
Fusing  Point,  about  4591°  F,  (?) 

Source.— Pt  \  is  chiefly  found  in  the  Ural  Mountains, 
where  it  occurs  in  alluvial  deposits,  usually  in  small, 
flattened  grains.  J 

Preparation. — The  "ore,"  as  it  is  called,  is  separated 
from  the  earthy  particles  by  washing.  The  grains  of  Pt  re- 
main behind  with  particles  of  Au,  FegO^.,  and  an  alloy  of  Os 
and  I  r.  §  The  Au  is  removed  by  amalgamation,  and  the  Fe 

*  This  paper  is  "  sensitized  "  by  floating  it  on  a  solution  of  sodium  chloride, 
and  then  on  one  of  silver  nitrate,  thus  filling  the  pores  of  the  paper  with  the 
silver  chloride,  which  is  extremely  sensitive  to  light. 

t  The  word  platinum  signifies  "little  silver." 

$  The  largest  nugget  ever  found  weighed  18  Ibs. 

§  Ir  is  named  from  Iris,  the  rainbow,  because  of  the  beautiful  color  of  its  salts 
8 


170  INORGANIC     CHEMISTRY. 

by  a  magnet.    The  Pi  is  then  dissolved  by  melted  Pb  and 
afterward  recovered  from  this  alloy  by  cupellation. 

Properties.— Pt  resembles  Ag  in  its  appearance.  It  is 
one  of  the  most  ductile  metals,  wire  being  made  from  it 
so  fine  as  to  be  invisible  to  the  naked  eye.  *  It  is  soluble 
in  aqua-regia,  but  not  in  the  simple  acids.  It  does  not 
oxidize  in  the  air,  is  the  most  infusible  of  metals,  and  can 
be  melted  only  by  the  heat  of  the  compound  blow-pipe 
or  voltaic  battery.  In  the  arts  it  is  fused  in  the  former 
manner.  These  properties  fit  it  for  use  as  crucibles,  and 
for  this  purpose  it  is  invaluable  to  the  chemist. 


MERCURY. 

Symbol,  Hg Atomic  Weight,  200 Specific  Gravity,  13,5, 

Melting  (Freezing)  Point,- 39°F. .  .Boiling  Point,  662°  F. 

MERCUKY  is  also  called  quicksilver,  because  it  runs 
about  as  if  it  were  alive,  and  was  supposed  by  the  alche- 
mists to  contain  silver.  It  was  known  very  anciently, 
and  the  mines  of  Spain  were  worked  by  the  Romans. 

Source.—  Cinnabar,  HgS,  a  brilliant  red  ore,  is  the 
principal  source  of  this  metaLf  When  sublimed  with  S, 
Hg  forms  the  pigment  known  as  "vermilion." 

in  solution.  When  combined  with  Os,  it  makes  "  iridosmine,"  used  for  the  nibs 
of  gold  pens. 

*  Wollaston's  Method,  as  it  is  called,  consists  in  covering  fine  platinum  wire 
with  several  times  its  weight  of  Ag,  and  then  drawing  this  through  the  plates 
used  for  drawing  wire  until  the  finest  hole  is  reached,  when  the  wire  is  placed 
in  HNO5,  which  dissolves  the  Ag  and  leaves  the  Pt  intact.  This,  in  the  form  of 
the  finest  wire  known,  may  be  found  in  the  solution  by  means  of  a  microscope. 
(See  Philosophy,  page  27.) 

t  Hg  is  found  native  in  Mexico  in  very  small  quantities,  where  the  mines  are 
said  to  have  been  discovered  by  a  slave,  who,  in  climbing  a  mountain,  came  to 
a  very  steep  ascent  To  aid  him  in  surmounting  this,  he  tried  to  draw  himself 


MERCURY.  171 

Preparation. — Hg  is  readily  prepared  by  roasting  HgS 
in  the  open  air.  The  S  passes  off  as  S02?  while  the  Hg 
volatilizes  and  is  condensed  in  earthen  pipes. 

Properties. — Hg  emits  a  vapor  at  all  temperatures  above 
40°  F.  Its  solvent  is  H  N03.  It  forms  an  amalgam  *  with 
gold  or  silver.  This  is  its  most  singular  property.  A 
gold  leaf  dropped  upon  mercury  disappears  like  a  snow- 
flake  in  water.  Particles  of  Ag  or  Au,  too  fine  to  be  seen 
by  the  eye,  will  be  found  by  Hg  and  gathered  from  a 
mass  of  ore. 

Uses. — Hg  is  extensively  employed  in  the  manufacture 
of  thermometers  and  barometers;  for  silvering  mirrors;  f 
and  for  extracting  the  precious  metals  from  their  ores. 

up  by  a  bush  which  grew  in  a  crevice  above.  The  shrub,  however,  giving  way, 
was  torn  up  by  the  roots,  and  a  tiny  stream,  of  what  seemed  liquid  silver,  trick- 
led down  upon  him. 

*  "  Several  years  ago,  while  lecturing  upon  chemistry  before  a  class  of  ladies, 
we  had  occasion  to  purify  some  quicksilver  by  forcing  it  through  chamois  skin. 
The  scrap  of  leather  remained  upon  the  table  after  the  lecture,  and  an  old  lady, 
thinking  it  would  be  very  nice  to  wrap  her  gold  spectacles  in,  accordingly  appro- 
priated it  to  this  purpose.  The  next  morning  she  came  to  us  in  great  alarm, 
stating  that  the  gold  had  mysteriously  disappeared,  and  nothing  was  left  in  the 
parcel  but  the  glasses.  Sure  enough,  the  metal  remaining  in  the  pores  of  the 
leather  had  amalgamated  with  the  gold,  and,  entering,  destroyed  the  spectacles. 
It  was  a  mystery,  however,  which  we  could  never  explain  to  her  satisfaction."— 
J.  R.  NICHOLS  in  Fireside  Science. 

t  Mirrors  were  anciently  made  of  steel  or  silver,  highly  polished.  They  were 
very  liable  to  rust  and  tarnish,  and  so  a  piece  of  sponge,  sprinkled  with  pum- 
ice-stone, was  suspended  from  the  handle  for  rubbing  the  mirror  before  use. 
Seneca,  in  lamenting  over  the  extravagance  of  his  time  among  the  old  Romans, 
says :  "  Every  young  woman  now-a-days  must  have  a  silver  mirrqr."  The  pro- 
cess of  silvering  ordinary  mirrors  is  briefly  as  follows  :  Tin-foil  is  first  spread 
evenly  upon  a  marble  table,  and  then  the  Hg  is  carefully  poured  over  it.  The 
two  metals  combine,  forming  a  bright  amalgam.  A  clean,  dry  plate  of  glass  is 
then  carefully  pushed  forward  over  the  table  so  as  to  carry  the  superfluous  Hg 
before  it,  and  also  prevent  the  air  from  getting  between  the  glass  and  the  amal- 
gam. Weights  are  afterwards  added  to  cause  the  film  to  cling  more  closely.  In 
twenty-four  hours  the  plate  is  removed,  and  in  three  or  four  weeks  is  dry  enough 
to  be  framed.  When  we  look  in  a  mirror  we  rarely  realize  what  it  has  cost 
others  to  thus  minister  to  our  comfort.  The  workmen  are  short-lived.  A  paral- 
ysis sometimes  attacks  them  within  a  few  weeks  after  they  enter  the  manufac- 
tory, and  it  is  thought  remarkable  if  a  man  escapes  for  a  year  or  two.  Its  effects 
are  similar  to  those  of  calomel ;  the  patient  dances  instead  of  walking,  and  can- 
not direct  the  motion  of  his  arms,  nor  in  some  cases  even  masticate  his  food. 


17%  INORGANIC     CHEMISTRY. 

The  action  of  Hg  on  the  human  system  is  too  well 
known  to  need  description.  "  In  its  metallic  state,  Hg 
has  been  taken  with  impunity  in  quantities  of  a  pound 
weight"  (American  Cyclopedia),  but  when  finely  divided, 
as  in  vapor,  mercurial  ointment,*  or  "  blue-pill,"  its  effects 
are  marked.  It  renders  the  patient  extremely  susceptible 
to  colds ;  acts,  as  is  generally  thought,  upon  the  liver,  in- 
creasing the  secretion  of  bile,  and  repeated  doses  pro- 
duce "salivation." 

Compounds.— Mercuric  Oxide,  HgO,  "red  preci- 
pitate," is  interesting,  as  the  substance  from  which 
Priestley  discovered  0  gas. 

Mercurous  Chloride,  HgCl,  Calomel,  is  a  white 
powder  used  in  medicine.  It  can  be  easily  distinguished 
from  corrosive  sublimate,  since  it  is  insoluble  in  H20, 
and  hence,  tasteless. 

Jlfemiric  Chloride,  HgCl2,  Corrosive  Sublimate,  is 
a  heavy,  white  solid,  soluble  in  H20,  and  with  a  burning 
metallic  taste.  It  has  powerful  antiseptic  properties,  and 
is  used  to  preserve  specimens  in  natural  history.  It  is  a 
deadly  poison.  Its  antidote  is  white  of  eggs,  milk,  etc. 


THE     ALLOYS. 

THESE  are  very  numerous,  and  many  of  them  possess 
properties  so  different  from  their  elements  that  they 
almost  seem  like  new  metals.  The  color  and  hardness 
are  changed,  and  sometimes  the  melting  point  is  below 

*  This  is  vulgarly  called  "anguintum,"  which  may  be  a  corruption  of  the 
Latin  term  unguentum  (unguent).    It  is  used  in  cutaneous  diseases. 


j  THE    ALLOYS.  173 

that  of  any  one  of  the  constituents.  The  proportions  of 
the  metals  used  vary.  The  following  is  a  fair  average  : 

2ype-melal  contains  3  parts  of  lead  *  to  1  of  anti- 
mony, f 

^Pewter  contains  4  parts  of  Sn  and  1  of  Pb. 

Britannia  consists  of  100  parts  of  Sn,  8  of  Sb,  2  of 
Bi,t  and  2  of  Cu. 

2$rass  is  2  parts  of  Cu  and  1  of  Zn. 

German  Silver  contains  Cu,  Zn,  and  Ni§  (brass 
whitened  by  nickel). 

Soft  Solder,  used  by  tinsmiths,  is  made  by  melting 
Pb  and  Sn  together,  the  usual  proportion  being  half-and- 
half. 

Hard  Solder  is  composed  of  Cu  and  Zn. 

Fusible  Metal  melts  at  201°,  and  spoons  made  of 
it  will  fuse  in  hot  tea.  It  can  be  melted  in  a  paper-cru- 
cible over  a  candle.  It  consists  of  Bi,  Pb,  and  Sn.  Yet 


*  An  improved  kind  lately  introduced  is  2  parts  Pb,  1  part  Sn,  and  1  Sb. 

t  Antimony  was  discovered  by  Basil  Valentine,  a  monk  of  Germany,  in  the 
fifteenth  century.  It  is  said  that,  to  test  its  properties,  he  first  fed  it  to  the 
ewine  kept  at  the  convent,  and  found  that  they  thrived  upon  it.  He  then  tried  it 
upon  his  fellow-monks,  but  perceiving  that  they  died  in  consequence,  he  forth- 
with named  the  new  metal,  in  honor  of  this  fact,  anti-moine  (anti-monk),  whence 
our  term  antimony  is  derived.  It  is  a  brittle,  bluish-white  metal,  with  a  beau- 
tiful laminated,  star-like,  crystalline  structure.  It  is  used  simply  as  an  alloy  for 
type-metal,  Britannia-ware,  etc.  Its  test  is  HaS,  which  throws  down  a  brilliant 
orange-colored  precipitate.  Melt  a  small  fragment  of  Sb  before  the  blow-pipe, 
and  throw  the  melted  globule  upon  an  inclined  plane.  It  will  instantly  dart  off 
in  minute  spheres,  each  followed  by  a  long  trail  of  smoke. 

%  Bismuth  is  a  reddish-white  metal  used  only  in  alloys  and  in  the  construction 
of  thermo-electric  piles.  (See  Philosophy,  page  313.) 

§  Ni,  like  Co,  is  a  constituent  of  meteorites.  It  is  mined  in  Pennsylvania  for 
the  United  States  government  to  make  into  cents.  Formerly  its  principal  use  was 
in  German  silver,  but  of  late  it  has  been  employed  extensively  in  the  manufac- 
ture of  the  best  plated-ware.  (See  Philosophy,  page  300.)  Its  silvery-whiteness, 
when  pure,  its  high  polish,  which  often  lasts  for  years,  and  its  hardness,  almost 
equal  to  that  of  steel,  eminently  fit  it  for  the  plating  of  mathematical  and  other 
delicate  instruments.  The  salts  of  Ni  have  a  handsome  green  tint.  The  rare 
gem  chrysoprase  is  colored  by  the  oxide. 


274  IN  O  K  G  A  NIC     CHEMISTRY. 

the  first  metal  melts  at  507°,  the  second  at  617°,  and  the 
third  at  442°. 

^Bronze  is  95  parts  of  Cu,  4  of  Sn,  and  1  of  Zn. 

Gold  is  soldered  with  an  alloy  of  itself  and  Ag ;  Sil- 
ver, with  itself  and  Cu ;  Copper,  with  itself  and  Zn  : 
the  principle  being  that  the  metal  of  lower  fusing  point 
causes  the  other  to  melt  more  easily. 

Coin .  — The  precious  metals,  when  pure,  are  too  soft 
for  common  use.  They  are  therefore  hardened  by  other 
metals.  The  gold  coin  of  the  United  States  consists  of  9 
parts  of  gold  and  1  of  alloy.  The  alloy  is  composed  of  9 
parts  of  Cu,  whitened  by  1  of  Ag,  so  as  not  to  darken  the 
gold  coin.  Silver  coin  is  9  parts  of  Ag  and  1  of  Cu.  The 
nickel  cent  is  88  parts  of  Cu  and  12  of  Ni.  Cu  being 
cheaper  than  Ni,  it  is  used  to  make  the  coin  larger. 
The  term  carat,  applied  to  the  precious  metals,  means 
•fa  part.  Therefore,  gold  18  carats  fine,  contains  J-f  of 
gold  and  fa  of  alloy. 

Shot  is  an  alloy  of  about  1  part  of  As  to  100  of  Pb. 
The  manufacture  is  carried  on  in  what  are  called  "  shot- 
towers,"  some  of  which  are  two  hundred  and  fifty  feet 
high.  The  alloy  is  melted  at  the  top  of  the  building,  and 
poured  through  colanders.  The  metal,  in  falling,  breaks 
up  into  drops,  which  take  the  "  spheroidal  form "  (See 
Philosophy,  pages  37  and  242),  harden,  and  are  caught  at 
the  bottom  in  a  well  of  water  which  cools  the  shot  and 
also  prevents  their  being  bruised  in  striking.  The  shot 
are  dipped  out,  dried,  and  then  assorted,  by  sifting  in  a 
revolving  cylinder,  which  is  set  slightly  inclined  and  per- 
forated with  holes,  increasing  in  size  from  the  top  to  the 
bottom.  The  shot  being  poured  in  at  the  top,  the  small 
ones  drop  through  first,  next  the  larger,  and  so  on/  till 


PROPERTIES     OF    THE    METALS.  175 

the  largest  reach  the  bottom.  Each  size  is  received  in  its 
own  box.  Shot  are  polished  by  being  agitated  for  several 
hours  with  black-lead,  in  a  rapidly  revolving  wheel. 
They  are  finally  tested  by  rolling  them  down  a  series 
of  inclined  planes  placed  at  a  little  distance  from  each 
other.  The  spherical  shot  will  jump  from  one  plane  to 
the  next,  while  the  imperfect  ones  will  fall  short,  and 
drop  below ;  or  sometimes,  by  rolling  down  a  single  in- 
clined plane,  the  spherical  ones  will  go  to  the  bottom, 
while  the  imperfect  ones  roll  off  at  the  sides. 

Oreide  is  a  beautiful  alloy  of  brass  resembling  gold, 
but  it  soon  tarnishes  by  exposure  to  the  air. 

Muminum  3$ronze,  or  gold,  is  an  alloy  of  Al  and 
Cu.  It  is  elastic,  malleable,  and  very  light.  It  strikingly 
resembles  gold,  and  is  much  used  instead  of  that  costly 
metal. 


REVIEW     OF    THE    PROPERTIES 
OF    THE    METALS. 

Oxidation. — K  and  Na  have  an  intense  attraction 
for  0,  while  Au  and  Ag  have  little  affinity  for  it,  and  are 
therefore  found  native.  -j- 

3)ensity.  —  L  is  the  lightest  liquid  known.  Pt  is 
the  heaviest  solid,  being  over  twenty-one  times  as  heavy 
as  H20,  while  K  and  Na  will  float  upon  it. 

Melting  (Point. — Hg  is  liquid  at  all  ordinary  tem- 
peratures. K  and  Na  melt  beneath  the  boiling  point  of 
H20  ;  Zn  below  a  red  heat,  and  Cu  above ;  Co,  Ni,  and 
wrought-iron  require  the  greatest  heat  of  the  forge 
(4000°),  while  Pt  and  Os  melt  only  in  the  flame  of  the 


176'  INORGANIC     CHEMISTRY. 

oxy-hydrogen  blow-pipe.  Sn  melts  at  the  lowest  temper- 
ature (442°)  of  any  of  the  ordinary  metals. 

Co2or.  — The  most  common  color  is  white,  of  varying 
shades.  It  is  nearly  pure  in  Ag,  Pt,  Cd,  and  Mg;  yellow- 
ish in  Sn  ;  bluish  in  Zn  and  Pb;  gray  in  Fe,  and  reddish 
in  Bi.  Cu  is  a  full  red,  and  Au  a  bright  yellow. 

Jlfa22eabi2ifry '. — Au,  Ag,  and  Cu  are  the  most  malle- 
able of  the  metals ;  Au,  Ag,  and  Pt  are  the  most  ductile. 

Utriltteness \ — Sb  and  Bi  may  be  easily  powdered ; 
Zn  may  be  broken  with  more  difficulty,  while  the  fibrous 
metals  are  exceedingly  tough. 

Tenacity.  —  Steel  is  the  most,  and  lead  the  least, 
tenacious  of  the  metals ;  the  proportion  being  as  1  to  42. 

Special  "Properties.  —  Certain  of  the  metals  are 
valuable  because  of  their  peculiar  properties.  Thus,  Hg, 
because  it  will  form  an  amalgam,  and  is  a  liquid  at  all  ordi- 
nary temperatures ;  Sb,  because  it  hardens  Pb  and  Sn  ;  Bi 
and  Cd,  because  they  render  Pb  and  Sn  more  easily  melted ; 
Ni,  because  it  whitens  Cu;  Mg,  for  its  brilliant  light; 
Au,  for  its  rarity  and  lustre ;  Fe,  for  the  diverse  properties 
it  can  assume  in  wrought  and  cast  iron,  and  in  steel,  and 
because  it  is  the  only  metal  which  can  be  used  for  the 
magnetic  needle  and  electro-magnet;  Cu,  for  its  duc- 
tility and  its  conductibility  of  electricity ;  and  Pt,  for  its 
infusibility. 

PRACTICAL     QUESTIONS. 

1.  Pb  is  softer  than  Fe  ;  why  is  it  not  more  malleable  ? 

2.  What  is  the  cause  of  the  changing  color  often  seen  in  the 
scum  on  standing  water  ? 

3.  How  can  the  spectra  of  the  metals  be  obtained  ? 

4.  Ought  cannon,  car-axles,  etc.,  to  be  used  until  they  break  or 
wear  out  ? 


PRACTICAL     QUESTIONS.  177 

5.  Why  is  "  chilled  iron  "  used  for  safes  ? 

6.  Does  a  blacksmith  plunge  his  work  into  water  merely  to 
cool  it? 

7.  What  causes  the  white  coating  made  when  we  spill  water 
on  zinc? 

8.  Is  it  well  to  scald  pickles,  make  sweetmeats,  or  fry  cakes  in 
a  brass  kettle  ? 

9.  What  danger  is  there  in  the  use  of  lead  pipes  ?    Is  a  lining 
of  Zn  or  Sn  a  protection  ? 

10.  Is  water  which  has  stood  in  a  metal-lined  ice-pitcher  health- 
ful? 

11.  If  you  ask  for  "cobalt"  at  a  drug-store,  what  will  you  get? 
If  for  "  arsenic  ?" 

12.  What  two  elements  are  fluid  at  ordinary  temperatures  ? 

13.  Should  we  touch  a  gold  ring  to  mercury  ?  * 

14.  Why  does  silver  blacken  if  handled  ? 

15.  Why  does  silver  tarnish  rapidly  where  coal  is  used  for  fires  ? 

16.  Why  is  a  solution  of  a  coin  blue  ? 

17.  Why  will  a  solution  of  silver  nitrate  curdle  brine  ? 

18.  Why  does  writing  with  indelible  ink  turn  black  when  exposed 
to  the  sun,  or  to  a  hot  iron  ? 

19.  What  alloys  resemble  gold  ? 

20.  Why  does  a  fish-hook  "  rust  out "  the  line  to  which  it  is  fas- 
tened ? 

21.  Why  do  the  nails  in  clap-boards  loosen  ? 

22.  Show  that  the  earth's  crust  is  mainly  composed  of  burnt 
metals. 

23.  What  kind  of  iron  is  used  for  a  magnet  ?    For  a  magnetic 
needle  ? 

24.  Why  does  a  tin  pail  so  quickly  rust  out  when  once  the  tin  is 
worn  through  ? 

25.  Why  is  the  zinc  oxide  found  in  New  Jersey  red,  when  zinc 
rust  is  white  ? 

26.  Should  we  filter  a  solution  of    permanganate    of    potash 
through  paper  ? 

27.  Why  is  wood,  cordage,  etc.,  sometimes  soaked  in  a  solution 
of  corrosive  sublimate  ? 

*  If  the  surface  is  only  whitened,  the  Hg  may  be  removed  with  dilute  HNO3, 
and  the  ring  be  polished  to  look  as  before.  The  Hg  will  soon  penetrate  the  gold 
and  render  it  brittle. 


178  INORGANIC     CHEMISTRY. 

28.  Why  does  the  white  paint  around  a  sink  turn  black  ? 

29.  Why  is  aluminum,  rather  than  platinum,  used  for  making 
the  smallest  weights  ? 

30.  How  would  you  detect  the  presence  of  iron  particles  in  black 
sand? 

31.  Which  metals  can  be  welded  ? 

32.  When  the  glassy  slag  from  a  blast-furnace  has  a  dark  color, 
what  does  it  show? 

33.  In  welding  iron  the  surfaces  to  be  joined  are  sometimes 
sprinkled  with  sand.     Explain. 

34.  What  is  the  difference  between  an  alloy  and  an  amalgam  ? 

35.  Steel  articles  are  blued  to  protect  from  rusting,  by  heating  in 
a  sand-bath.     Explain. 

36.  Give  the  rational  formulae  for  copperas  and  white  lead. 

37.  Why  is  Hg  used  for  filling  thermometers  ? 

38.  What  oxide  is  formed  by  the  combustion  of  Na,  K,  Zn,  S,  Fe, 
Pb,  Cu,  P,  etc.?    Which  are  bases?    Acids?    Give  the  common 
name  of  each. 

39.  Is  charcoal  lighter  than  H20  ? 

40.  Name  the  vitriols. 

41.  Is  Mg  a  monad  or  a  dyad?    Zn  ? 

42.  Name  some  dibasic  acid. 

43.  Name  a  neutral  salt.     An  acid  salt. 

44.  Calculate  the  percentage  of  water  contained  in  crystallized 
copper  sulphate.     Sodium  sulphate.    Calcium  sulphate.     Alum. 

45.  What  is  the  test  for  Ag  ?    Cu  ? 

46.  What  weight  of  crystallized  "tin  salts"  (SnCl2,2H20)  can  be 
prepared  from  one  ton  of  metallic  tin  ? 

47.  100  parts   by  weight  of  silver  yield  132.8  -f  parts  of  silver 
chloride.     Given  the  combining  weight  of  chlorine,  required  that 
of  silver. 

48.  What  is  the  composition  of  slaked  lime  ? 

49.  How  is  ferrous  sulphate  obtained  ?    How  many  tons  of  crys- 
tals can  be  obtained  by  the  slow  oxidation  of  230  tons  of  iron 
pyrites  containing  37.5  per  cent,  of  sulphur  ? 

50.  Required  500  tons  of  soda  crystals  ;  what  will  be  the  weight 
of  salt  and  pure  sulphuric  acid  needed  ? 

51.  Describe  the  uses  of  lime  in  agriculture. 

52.  How  many  tons  of  oil  of  vitriol,  containing  70  per  cent,  of 
pure  acid  (H2S04),  can  be  prepared  from  250  tons  of  iron  pyrites, 
containing  42  per  cent,  of  sulphur  ? 


III. 

iDrgantc   iChemistry. 


"Thus  the  Seer, 
With  vision  clear, 
Sees  forms  appear  and  disappear, 
In  the  perpetual  round  of  strange, 
Mysterious  change 

From  birth  to  death,  from  death  to  birth, 
From  earth  to  heaven,  from  heaven  to  earth; 
Till  glimpses  more  sublime 
Of  things,  unseen  before, 
Unto  his  wondering  eyes  reveal 
The  Universe  as  an  immeasurable  wheel 
Turning  forevermore 
In  the  rapid  and  rushing  river  of  Time." 

LONGFELLOW. 


ORGANIC   CHEMISTRY, 


INTRODUCTION. 

Necessity  of  Organization. — We  have  thus  far 
spoken  of  the  various  elements  of  matter.  We  have 
found  many  which  are  necessary  to  the  growth  of  our 
bodies,  but  still  we  cannot  live  upon  them.  We  need 
phosphorus,  but  we  cannot  eat  it,  for  it  is  a  deadly  poison. 
We  need  Fe,  but  it  would  make  a  most  unsavory  diet. 
We  need  CaO,  but  it  would  corrode  our  flesh.  We  need 
H,  but  it  must  be  combined  with  0  as  H20  to  be  of 
any  value  to  us.  We  need  C,  but  charcoal  would  form  a 
very  indigestible  food.  If  we  were  shut  up  in  a  room 
with  all  the  elements  of  nature,  we  not  only  could  not 
combine  them  so  as  to  produce  those  organic  substances 
necessary  to  our  life  and  comfort,  but  we  should  actually 
die  of  starvation.  We  thus  find  that  the  mineral  matter 
must  be  organized  in  some  manner  before  we  can  use  it 
to  advantage. 

^Plants  Organize  Matter. — We  have  seen  tha,t 
in  the  plant  the  sunbeam  decomposes  the  poisonous  C02 
and  furnishes  us  the  life-giving  0 ;  that  we  cannot  create 
force  ourselves,  or  draw  it  direct  from  the  sun,  but  must 
take  that  which  the  plant  has  hoarded  for  us.  We  shall 


182  ORGANIC    CHEMISTRY. 

now  find  that,  in  addition,  the  plant  changes  inorganic 
matter  to  organic.  It  takes  up  the  elements  we  need  for 
our  growth  and  for  use  in  the  arts,  and  combines  them 
into  plant-products,  such  as  wood,  starch,  sugar,  etc.  — 
We  are  thus  dependent  upon  the  vegetable  world  for  the 
grand  staples  of  commerce  and  of  luxury — all  that  we 
eat,  drink,  or  wear.  Each  tiny  leaf,  every  tree  and  shrub, 
every  spire  of  grass  even,  is  working  constantly  for  us. 
The  earth  was  once  a  burnt  body — the  cinders  of  the  vast 
fire  amid  which  it  had  its  origin.  (See  Geology,  page  17.) 
Every  organized  substance  now  on  its  surface  has  been 
rescued  from  the  grasp  of  0  by  the  plants. 

^Difference  between  Organic  and  Inorganic 
^Bodies. — 1.  While  inorganic  bodies  deal  with  sixty- 
three  elements,  organic  are  composed  principally  of  only 
four,  C,  H,  0,  and  N.  As  C  is  their  characteristic  ele- 
ment, they  are  frequently  styled  the  "  carbon  compounds." 
2.  While  inorganic  molecules  consist  of  only  a  few  atoms, 
and  are  therefore  very  simple  in  their  construction,  as : 
H20,  CO 2)  K20,  organic  frequently  contain  a  large  num- 
ber, and  are  extremely  complex,  as:  Sugar  =  C|2H22On, 
having  45  atoms  in  a  molecule;  stearin  =  C57H|,006, 
having  173  atoms;  albumen  =  C72H,,0N,8S022,  having 
222  atoms,  and  even  more,  according  to  some  author- 
ities. 3.  While  inorganic  bodies  are  formed  and  re- 
main fixed  in  one  state  under  the  influence  of  chemical 
affinity,  organic  grow  rapidly,  change  constantly,  and 
when  life  ceases,  as  rapidly  decay,  and  are  transformed 
into  inorganic  substances.  4.  Owing  to  their  complex 
structure,  and  the  presence  in  many  of  them  of  the  nega- 
tive N,  they  form  most  unstable  compounds.  In  this  we 
find  the  cause  of  their  quick  decay.  The  vital  principle 


ALLOTROPISM.  183 

alone  holds  them  together,  frequently  in  opposition  to 
the  laws  of  chemical  affinity ;  and  the  instant  that  is  re- 
moved, the  tendency  is  to  seek  new  affinities  and  form 
new  compounds.  On  the  other  hand,  inorganic  are  gen- 
erally burnt  bodies.  Their  chemical  affinities  are  satis- 
fied, and  hence  at  rest. 

The  Number  of  Carbon  Compounds  greatly 
exceeds  that  of  all  the  other  elements  combined,  and  is 
constantly  increasing.  The  labor  of  modern  chemists  is 
largely  devoted  to  the  subject,  and  the  field  opens  and 
broadens  with  every  discovery.  The  methods  of  classifi- 
cation are  unsettled,*  and  new  and  conflicting  theories 
yet  contend  on  this  border-ground  of  chemical  knowl- 
edge. 

Isomerism .  — Isomeric  compounds  are  those  which 
consist  of  the  same  elements  in  the  same  proportion. 
—  Example:  Sugar  and  gum-arabic  have  the  same 
molecular  formula,  C|2H220||.  —  GELIS.  The  difference 
between  such  compounds  has  been  supposed  to  lie  in  a 
dissimilar  grouping  of  the  atoms  about  each  other,  as  the 
same  pieces  upon  a  checker-board  may  be  variously  ar- 
ranged ;  or  as  the  letters  p-l-e-a  may  also  spell  1-e-a-p,  or 
p-e-a-1,  or  p-a-l-e  :  yet  nothing  is  definitely  known. 

A22olropism .  — The  individual  elements  are  also  sus- 
ceptible of  allotropic  states ;  as,  for  instance,  the  C  in  a 
compound  may  be  in  any  one  of  its  three  allotropic  forms. 
These  two  principles  of  isomerism  and  allotropism  run 
through  organic  chemistry,  and  account,  in  some  measure, 
for  the  immense  number  of  its  compounds.  Still,  one 

*  Even  Miller,  in  his  great  work  on  the  Elements  of  Chemistry,  which  em- 
bodies the  best  results  of  modern  research,  uses  the  same  division  as  the  older 
authorities,  and  nearly  the  same  as  that  which  was  adopted  in  the  former  edition 
of  this  work. 


184 


ORGANIC     CHEMISTRY. 


can  hardly  understand  how  olefiant  gas  and  india-rubber, 
the  fragrance  of  a  rose  and  the  odor  of  a  kerosene-lamp, 
should  consist  of  the  same  elements,  C  and  H,  only  in 
varying  proportions. 


STARCH,  WOODY  FIBRE,  AND  SUGAR, 


Fig.  68. 


1.     STARCH. 

(C6HI005.) 

Source.  —  Plants  ac- 
cumulate it,  1,  in  their 
roots,  as  the  carrot,  the 
turnip,  etc. ;  2,  in  sub- 
terranean stems,  as 
the  potato,  of  which  it 
forms  about  20  per 

My  69. 


Potato  Starch. 

cent. ;  3,  in  the  base  of 
their  leaves,  as  the  on- 
ion ;  4,  in  the  seed,  as 
corn,  of  which  it  forms 
about  80  per  cent.;  5, 
in  the  embryo,  as  the 
bean,  the  pea,  etc.  In 
all  these  it  is  stored  up 
for  the  future  growth  of 
the  plant.  It  is  kept  in 
its  starch  form  (lest  it 


Wheat  Starch. 


STARCH.  185 

dissolve  in  the  first  rain),  and  then  turned  to  sugar 
only  when  the  plant  needs  it  in  growing.  (See  p.  194.) 
Under  the  microscope,  each  vegetable  is  found  to  have  its 
peculiar  form  of  starch  granule,  so  that  in  this  way  any 
adulteration  is  easily  detected.* 

Preparation. — Starch  is  made  from  wheat,  corn,  pota- 
toes, etc.  The  process  is  essentially  the  same  in  all.  The 
potato,  for  example,  is  ground  to  a  pulp,  and  then  washed 
with  cold  water.  The  starch  settles  from  this  milky  mass 
as  a  fine,  white  precipitate. 

Properties. —  Starch  is  insoluble  in  cold  water;  in  hot, 
it  absorbs  H20,  swells,  and  the 
granules  burst,  forming  a  jelly- 
like  liquid,  used  for  starching. 
The  swelling  of  rice,  beans,  etc., 
when  cooked,  is  owing  to  this 
property.  By  heating  to  400° 
when  dry,  starch  undergoes  a 

peculiar    Change    into   a  Substance      Bursting  of  Starch  Granule. 

known   as   dextrine,  f   used   as    a 

mucilage  on  envelopes  and  adhesive  stamps,  for  making 
"  fig-paste,"  and  stiffening  chintzes.  The  test  of  starch  is 
I,  which  forms  in  solution  the  blue  iodide  of  starch.  Sago 
is  the  starch  from  the  pith  of  the  palm-tre'e ;  tapioca  and 


*  u  The  structure  of  the  grains  of  starch  is  very  beautifully  displayed  hy  placing 
some  of  them  in  contact  with  a  drop  of  concentrated  solution  of  zinc  chloride 
(tinged  with  a  little  free  iodine)  on  the  field  of  the  microscope.  No  change  takes 
place  in  the  granules  until  a  little  water  is  added.  They  then  become  of  a  deep 
blue  color,  and  gradually  expand ;  at  first  a  frill-like  plaited  margin  is  developed 
around  the  globule  ;  by  degrees  this  opens  out ;  the  plaits  upon  the  globule  may 
then  be  seen  slowly  unfolding,  and  may  be  traced  in  many  cases  into  the  wrin- 
kles of  the  frill ;  ultimately  the  granules  swell  up  to  twenty  or  thirty  times  their 
original  bulk,  and  present  the  appearance  of  a  flaccid  sac."— BUSK. 

t  Dextrine  is  isomeric  with  starch,  but  is  not  discolored  by  I. 


186  ORGANIC     CHEMISTRY. 

arrow-root  are  made  from  the  roots  of  South  American 
marshy  plants.* 

GUM  is  found  in  the  juices  of  nearly  all  plants,  and 
frequently  exudes,  as  in  the  peach,  plum,  and  cherry.  It 
is  soluble  in  water,  but  not  in  alcohol.  Gum-arabic,  which 
flows  in  transparent  tears  from  an  acacia  tree,  is  the 
purest  form.f  Mucilage,  which  occurs  in  gum  tragacanth, 
linseed,  quince-seed,  etc.,  is  a  modification  of  gum,  and  is 
insoluble  in  H20.  It  forms  with  it,  however,  a  gelatinous 
liquid,  which  is  exceedingly  useful. 

Vegetable  Jelly. — A  variety  of  gum  called  pectose 
exists  in  nearly  all  fruits  and  vegetables.  It  gives  to 
them  their  hardness  while  green. — FKEMY.  In  the  pro- 
cess of  ripening,  or  by  heat,  acids,  etc.,  it  is  turned  into 
pectin.  We  find  this  abundant  in  the  thick  juice  which 
exudes  from  an  apple  while  baking.  In  the  making  of 
jellies,  pectose  is  converted  into  a  mixture  of  pectosic 
and  pectic  acids. 


2.     WOODY      FIBRE      (C6H1006). 

Sources. — If  a  thin  slice  of  wood  be  examined  under 
the  microscope,  it  will  be  seen  to  consist  of  a  fibrous  sub- 
stance incrusted  and  compacted  with  woody  matter.  The 
former  is  called  cellulin  (C6H  |005).t  It  composes  the  cells 


*  Very  many  of  the  farinaceous  preparations  sold  for  the  sick  and  invalid, 
under  high-sounding  names,  are  simply  wheat  or  corn  starch. 

t  It  is  a  soluble  salt,  being  composed  of  arabic  acid  (C^H^Ou,  Gelis),  com- 
bined with  K  and  Ca. 

$  It  is  probable  that  the  molecule  of  woody  fibre  is  some  multiple  of  this  for 
mula,  as  C18H,0O15. 


WOODY    FIBRE.  187 

of  all  plants,  giving  them  strength  and  firmness,  and  is 
found  even  in  delicate  fruits,  holding  their  luscious  juices. 
It  occurs  in  various  modifications,  in  wood,  nut-shells,  and 
fruit-stones.  In  the  heart  of  a  tree,  its  cells  are  hard  and 
dense;  in  the  outer  part,  they  are  soft  and  porous;  in 
elder-pith  and  cork,  light  and  spongy ;  in  flax  and  cotton, 
long,  pliable,  and  fibrous ;  in  the  bran  of  wheat  and  corn, 
digestible. 

Secretion.  —  All  vegetation  consists  of  these  simple 
cells.  They  seem  alike  to  the  eye,  yet  they  have  a  very 
diverse  power  of  secretion.  The  cell  of  the  sugar-maple 
converts  its  sap  into  sugar ;  the  milk-weed,  into  a  milky 
juice;  the  caoutchouc,  into  rubber;  the  rhubarb-plant, 
into  oxalic  acid ;  and  the  rose-petal,  into  the  most  delicate 
of  perfumes. 

Cells  are  always  true  to  themselves.  There  seems  to  be 
a  law  of  God  stamped  on  each  one,  so  that  when  we  cut  a 
tiny  bud  from  one  tree  and  graft  it  into  another,  it  remains 
consistent  with  itself.  It  develops  into  a  limb,  and  years 
pass  by.  The  few  single  cells  become  a  myriad,  yet  they 
have  not  changed.  The  sap  flows  upward  in  the  tree ; 
but  at  a  certain  point — a  hidden  threshold  which  no 
human  eyft  can  discern,  it  comes  under  a  new  and  strange 
influence.  Here  it  is  transformed,  and  produces  fruit 
and  flowers,  in  accordance  with  another  and  different 
growth.  Somehow  quince- juice  is  made  into  pears, 
locust-juice  blooms  out  into  fragrant  acacias,  and  sweet 
and  sour  apples  hang  upon  the  same  limb. 

Uses. — These  are  wonderfully  various.  Woody  fibre  is 
woven  into  cloth,  built  into  houses,  twisted  into  rope, 
twine,  and  thread,  pressed  into  paper,  cut  into  fuel, 
carved  into  furniture.  We  eat  it3  wear  it,  walk  on  it, 


188  ORGANIC     CHEMISTRY. 

write  on  it,  sit  on  it,  print  on  it,  pack  our  clothes  in  it, 
sleep  in  it,  ride  in  it,  and  burn  it. 

PAPER  is  made  from  cotton,  linen,  straw,  or  any  sub- 
stance containing  cellular  tissue.  The  finest  writing- 
paper  is  manufactured  from  linen  rags.  These  are  first 
"  shredded  "  upon  scythe-blades — i.  e.,  the  seams  are  ripped 
open,  buttons  cut  off,  and  the  dust  shaken  out.  2d. 
They  are  steamed  in  a  solution  of  chloride  of  lime  for  ten 
or  twelve  hours  until  they  are  thoroughly  bleached.  3d. 
They  are  received  by  a  machine  that  alternately  lacerates 
them  by  a  cylinder  set  with  razor-like  blades,  and  washes 
them  with  pure,  cold  water  for  six  hours,  until  they 
are  reduced  to  a  mass  resembling  rice  and  milk.  4th. 
This  pulp  receives  a  delicate  blue  tint  from  smalt.*  5th. 
It  is  diluted  with  H20  nearly  to  the  consistency  of  milk, 
and  strained  to  remove  the  waxed  ends  and  knots  of 
thread  that  cause  the  little  lumps  which  catch  our  pen 
when  we  write  rapidly  on  poor  paper.  6th.  It  flows  over 
an  endless  belt  of  wire-gauze,  about  thirty  feet  in  length, 
through  which  the  water  steadily  drips  from  the  pulp,  as 
it  slowly  passes  along,  gaining  consistency  and  firmness. 
7th.  It  comes  to  a  part  of  the  belt  called  the  "  dandy- 
roll,"  consisting  of  a  cylinder,  on  the  surface  of  which  are 
wires  arranged  in  parallel  rows,  or  fancy  letters,  which 
print  upon  the  moist  paper  a  design — constituting  what 
is  termed  "laid,"  or  "wire-woven,"  paper.  8th.  The 
paper,  very  soft  and  moist  as  yet,  passes  between  rollers 
that  squeeze  out  the  water ;  then  between  others  which 
are  hot,  and  dry  it.  9th.  It  comes  to  a  vat  of  sizing,  com- 
posed of  glue  and  alum,  into  which  it  plunges,  and  at  the 

*  Powdered  glass  colored  with  oxide  of  cobalt. 


WOODY    FIBRE.  189 

opposite  side  emerges  only  to  go  between  other  rollers  that 
press  and  dry  it — at  the  end  of  which  it  passes  under  a 
cylinder,  set  with  knives  that  clip  the  roll  into  sheets  of 
any  desired  size. 

"Paper  ^Parchment  is  prepared  by  plunging  unsized 
paper  for  a  few  seconds  in  H2S04  of  a  specified  strength, 
then  washing  off  the  acid.  This,  in  some  unknown  way, 
changes  its  appearance  and  character,  so  that  it  resembles 
parchment,  while  its  toughness  is  five  times  that  of  the 
paper  from  which  it  was  made. — HOFMAK:^. 

Z/inen  is  made  from  the  inner  bark  of  flax.  The 
plant  is  first  pulled  from  the  ground  to  preserve  the  en- 
tire length  of  the  stalk ;  next  "  rotted "  by  exposure  to 
air  and  moisture,  when  the  decayed  outer  bark  is  removed 
by  "breaking;"  then,  by  " hatcheling,"  the  long,  fine 
fibres  are  divided  into  shreds,  and  laid  parallel,  while  the 
tangled  ones  are  separated  as  "  tow."  It  is  then  bleached 
on  the  grass,  which  renders  the  gray  coloring-matter  sol- 
uble by  boiling  in  lye.  The  whitened  flax  is  lastly  woven 
into  cloth. 

COTTOK  consists  of  the  beautiful  hollow,  white  hairs 
arranged  around  the  seed  of  the  cotton-plant.  As  it  is 
always  pure  and  white — except  Nankin  cotton,  which  is 
yellow — it  would  require  no  bleaching  did  it  not  become 
soiled  in  the  process  of  spinning,  etc. 

'Pyroxylin  (pur,  fire,  and  xulon,  wood),  Gun- Cotton, 
is  prepared  by  dipping  cellular  tissue — cotton,  saw-dust, 
printing-paper,  etc. — in  a  mixture  of  HN03  and  H2S04  of 
a  certain  specific  gravity.  It  is  then  carefully  washed 
and  dried.  It  is  not  materially  changed  in  appearance, 
but  a  part  of  its  H  has  been  replaced  by  N02>  and  it  has 
become  very  inflammable.  It  will  burn  at  a  temperature 


190  ORGANIC     CHEMISTRY. 

more  than  200°  below  that  required  to  ignite  gunpowder, 
while  its  explosive  force  is  much  greater. — MILLEE. 

Collodion  is  a  solution  of  gun-cotton  in  sulphuric 
ether  and  alcohol.  It  forms  a  syrupy  liquid,  which  is 
much  used  by  photographers. 

3  .      SUGAR. 

CANE-SUGAR  (C^H^O,,),*  Sucrose,  is  obtained  from 
the  sap  of  the  sugar-maple,  and  the  juice  of  the  sugar-cane, 
sorghum,  and  beet.  In  making  it  from  the  sugar-cane, 
the  canes  are  crushed  between  iron  cylinders,  to  express 
the  juice.  As  the  liquid  sours  very  soon,  from  the  heat 
of  the  climate  in  which  it  grows,  a  little  lime  is  added  to 
neutralize  the  acid,  and  it  is  then  evaporated  to  a  thick 
jelly,  and  set  aside  to  cool.  The  sugar  crystallizes  read- 
ily, forming  brown  sugar,  which  is  put  in  perforated  casks 
to  drain.  The  drainings,  "mother-liquor,"  constitute 
molasses. 

ffie fining \ — Brown  sugar  is  dissolved  in  H20,  filtered 
through  twilled  cotton  to  remove  the  coarse  impurities, 
and  then  through  a  deep  layer  of  animal  charcoal.  The 
colorless  solution  is  next  evaporated  in  vacuum  pans  from 
which  the  air  is  exhausted,  so  that  the  sugar  boils  at  so 
low  a  temperature  as  to  avoid  all  danger  of  burning. 
When  sufficiently  concentrated,  the  liquid  is  removed  and 
set  aside  to  crystallize.  If  the  mass  of  crystals  is  dried  in 
moulds,  it  forms  loaf  sugar  ;  if  in  centrifugal  machines, 


*  A  very  brilliant  experiment  showing  the  presence  of  C  in  CmHaaOn  is 
obtained  by  putting  on  a  clean,  white  plate,  a  mixture  of  finely  pulverized  white 
engar  and  KC1O3.  Upon  adding  a  few  drops  of  H2SO4  a  vivid  combustion  will 
ensue.  By  mixing  with  the  sugar  a  few  iron  and  steel  filings,  and  performing 
the  experiment  in  a  dark  room,  or  out  of  doors  at  night,  fiery  rosettes  will  flash 
through  a  rose-colored  flame,  and  produce  a  fine  effect. 


WOODY    FIBRE.  191 

granulated  sugar.*  The  drainings  constitute  "syrup," 
"  sugar-house  molasses,"  etc. 

Confectionery.  —  Terra  alba  (white  earth),  is  im- 
ported from  Ireland  for  use  in  lozenges,  drops,  etc.f 
Confectionery  is  often  colored  by  dangerous  poisons,  so 
that  prudence  would  forbid  the  use  of  any  colored  candy. 
Licorice  drops  are  frequently  only  the  poorest  brown 
sugar,  terra  alba,  and  a  flavoring  of  licorice  to  make  the 
unwholesome  mixture  palatable.  Gum-drops  are  made, 
not  from  gum-arabic,  but  generally  of  a  species  of  glue 
manufactured  out  of  hoofs,  parings  of  hides,  etc.  How- 
ever repugnant  it  may  appear,  this  substance  is  perfectly 
clean  and  wholesome.  Eock  candy  is  formed  by  suspend- 
ing threads  in  a  strong  solution  of  sugar.  It  crystallizes 
upon  the  rough  surface  in  large,  six-sided  prisms. 

Caramel,  familiarly  called  burnt  sugar,  is  formed 
whenever  sugar  is  heated  to  about  420°,  as  when  sweet- 
meats boil  over  on  the  stove;  H20  is  lost  and  C  remains 
in  excess.  It  is  used  by  confectioners  and  for  coloring 
liquors. 

GRAPE-SUGAR  (C6HI206),  Dextrose,  is  found  in  honey, 
figs,  and  many  kinds  of  fruit.  Its  sweetening  power  is 
about  two-fifths  that  of  cane-sugar. 

Sugar  from  Starch.  —  The  difference  in  the  con- 
stitution of  starch  and  grape-sugar  is  only  H20.  By 

*  This  apparatus  consists  of  a  cylindrical  drum  mounted  upon  a  vertical  axis, 
to  which  a  rapid  rotary  movement  can  be  given.  The  outer  side  of  this  drum  is 
made  of  a  stout  but  closely-woven  network.  The  drum  is  inclosed  in  a  large, 
fixed,  cylindrical  vessel  capable  of  holding  the  liquid  which  may  pass  out  through 
the  network.  A  charge  of  syrup  is  placed  in  the  inner  drum,  which  is  then  made 
to  revolve  rapidly.  The  syrup  escapes  through  the  wire-gauze  into  the  outer 
drum  while  the  crystals  are  rapidly  dried. 

t  We  can  and  should  test  all  the  candy  we  purchase  by  putting  a  small  piece  in 
a  glass  of  water.  Whatever  settles  to  the  bottom  and  remains  undissolved  is  an 
adulteration. 


192  ORGANIC     CHEMISTRY. 

slowly  heating  potato-starch  with  dilute  H2S04  ^  *s 
transformed  into  a  syrup,  from  which  the  dextrose  will 
separate  in  crystals.  The  weight  of  the  sugar  will  exceed 
that  of  the  starch  by  the  additional  H  20.  The  acid  acts 
by  catalysis,  being  itself  unchanged  in  the  process.* 

f  f  Candied  J~e22ies,  ^Preserves,  etc ."  —  The 
sugar  of  many  kinds  of  ripe  fruits  consists  of  grape  or 
cane  sugar  mixed  with  fruit  sugar.  The  latter  changes 
gradually  into  grape  sugar,  and  crystallizes  as  in  honey, 
dried  figs,  etc.f 


FERMENTATION. 

If  a  solution  of  starch  or  grape-sugar  be  exposed  to  the 
air  it  will  undergo  no  change ;  but  if  there  be  added  a 
little  ferment,  {  or  any  albuminous  substance  (i.  0.,  one 

*  Saw-dust,  paper,  and  even  rags  can  in  the  same  way  be  converted  into  sugar. 
Indeed,  Prof.  Pepper  speaks  of  seeing  some  made  out  of  an  old  shirt.  Wonderful 
beyond  our  comprehension  is  that  chemical  force  which  can  transform  a  cast-off 
garment  into  a  substance  which  will  delight  the  palate,  or  a  snowy  page  on  which 
thought  may  be  inscribed.  Thus  the  chemist  faintly  imitates  nature,  which, 
ever  out  of  waste  and  refuse,  springs  afresh.  The  fair  petals  of  the  lily  rest  upon 
the  black  mud  of  the  swamp,  and  the  products  of  decay  come  back  to  us  in 
objects  of  use  and  forms  of  beauty. 

+  Grape  sugar  is  isomeric  with  trait  sugar,  but  is  much  sweeter.  The  former, 
as  it  is  noted  for  its  right-handed  rotation  of  the  plane  of  polarized  light,  is  called 
dextrose  (dextra,  right),  and  the  latter,  from  its  left-handed  rotation,  laevulose 
(laws,  left).  (See  Philosophy,  p.  212.) 

$  In  many  cases,  spontaneous  fermentation  sets  in  without  the  apparent 
addition  of  any  ferment :  thus  wine,  beer,  milk,  etc.,  when  allowed  simply  to 
stand  exposed  to  the  air,  become  sour,  or  otherwise  decompose.  These  changes 
are,  however,  not  effected  without  the  presence  of  vegetable  or  animal  life,  and 
are  true  fermentations :  the  sporules,  or  seeds  of  these  living  bodies,  always  float 
about  in  the  air,  and  on  dropping  into  the  liquid  begin  to  propagate  themselves, 
and  in  the  act  of  growing  evolve  the  products  of  the  fermentation.  If  the  above 
liquids  be  left  only  in  contact  with  air  which  has  been  passed  through  a  red-hot 
platinum  tube,  and  thus  the  living  sporules  destroyed ;  or  if  the  air  be  simply 
filtered  by  passing  through  cotton  wool,  and  the  sporules  prevented  from  coming 
into  the  liquid,  it  is  found  that  these  fermentable  liquids  may  be  preserved  for 
any  length  of  time  without  undergoing  the  slightest  change.— BOSCOE. 


FERMENTATION.  193 

containing  N),  in  a  decomposing  state,  it  will  immedi- 
ately commence  breaking  up  into  new  compounds.  The 
ferment  acts  by  catalysis,  its  presence  seeming  to  over- 
come the  unstable  equilibrium  of  the  chemical  forces, 
and  causing  the  large  molecules  to  drop  into  smaller 
ones.  There  are  two  stages  in  this  chemical  change. 

1st.  A2coho2ic  Fermentation.  —  In  this,  the  grape- 
sugar  is  resolved  into  alcohol  and  carbonic  anhydride. 
The  former  remains  in  the  liquid,  while  the  latter 
escapes  in  little  bubbles  of  gas.  The  reaction  may  be 
represented  thus:  C6HI206=2C2H60  +  2C02. 

2d.  JLcetic  Fermentation.* — The  second  stage 
succeeds  the  first  immediately,  if  not  checked,  and  by  ab- 
sorbing 0  from  the  air,  the  alcohol  is  broken  up  into 
acetic  acid  and  ivater;  thus,  C2H60  +  02  (from  the  air)  = 
C2H402  +  H20. 

ICeast  is  formed  during  the  process  of  fermentation. 
It  consists  of  microscopic  plants  (Mycoderma  cerevisice) 
which  increase  by  the  formation  of  multitudes  of  tiny 
cells  not  more  than  ^|n  of  an  inch  in  diameter.  In  the 
brewing  of  beer  they  spring  up  in  great  abundance,  mak- 
ing common  brewer's  yeast. f 

fyfatt.  —  In-  making  malt,  the  barley  is  thoroughly 
soaked  in  water,  and  then  spread  on  the  floor  of  a  dark 
room,  to  heat  and  sprout.  Here  a  curious  change  ensues, 
identical  with  that  which  takes  place  in  every  planted 
seed.  Each  one  contains  starch  and  a  nitrogenous  sub- 


*  There  are  also  other  forms  of  fermentation,  as  the  lactic,  yielding  lactic  acid— 
the  acid  of  sour  milk ;  hutyric,  yielding  butyric  acid,  etc. 

t  The  yeast-cakes  of  the  kitchen  are  formed  by  exposing  moistened  Indian 
meal,  containing  a  ferment,  to  a  moderate  temperature,  until  the  gluten  or  albu- 
minous matter  of  the  cakajias  undergone  this  alcoholic  fermentation.  They  are 
then  laid  aside  for  use. 

9 


194  ORGANIC     CHEMISTRY. 

stance  called  gluten.  The  tiny  plant  not  being  able  to 
support  itself  in  the  beginning,  has  here  a  little  patri- 
mony with  which  to  start  in  life ;  but,  as  the  starch  is 
insoluble  in  the  sap,  it  must  first  be  changed  to  a  soluble 
form.  We  see,  therefore,  the  need  of  a  ferment ;  but  it 
would  not  answer  to  store  up  in  the  seed  an  active  fer- 
ment, as  that  might  cause  a  change  before  the  plant  was 
ready  to  grow,  and  thus  the  plant's  capital  be  wasted. 
The  gluten  acts,  therefore,  as  a  latent  ferment.  As  soon 
as  the  seed  is  planted  it  absorbs  moisture  from  the  ground, 
is  turned  into  diastase — an  active  ferment  * — the  starch 
is  converted  into  dextrine  and  sugar,  dissolved,  and  imme- 
diately applied  to  the  uses  of  the  growing  plant.  This 
change  takes  place  in  the  malting-room.  The  barley 
sprouts,  and  a  part  of  its  starch  is  turned  to  sugar,  so  as 
to  give  it  a  sweetish  taste.  If  this  germination  were 
allowed  to  proceed,  the  little,  barley  sprout  would  turn 
the  sugar  into  woody  fibre.  To  prevent  this,  the  grain  is 
heated  in  a  kiln  until  the  germ  is  destroyed.  Barley  in 
this  condition  is  called  malt,  and  is  then  transported  to 
the  breweries. 

^Brewing  ?Beer.  — The  malt  is  crushed  and  digested 
in  water,  to  convert  the  remaining  starch  into  dextrine 
and  sugar.  Hops  and  yeast  are  added,  and  fermentation 
immediately  commences.  Bubbles  of  gas  rise  to  the  top 
with  a  low  hissing  sound,  yeast  gathers  in  a  foamy  cream 
that  comes  to  the  surface  of  the  tub,  while  the  alcohol 
gradually  accumulates  in  the  liquid.  The  beer  is  now 
drawn  off  into  tight  casks,  where  it  undergoes  a  second 


*  Malt  does  not  contain  more  than  5^  of  its  weight  of  diastase ;  one  part  of 
this  substance  being  sufficient  to  change  2,000  parts  #f  starch  into  dextrine  and 
sugar.— PBBSOZ  ANP  PATEN, 


FERMENTATION.  195 

fermentation ;  the  flavor  ripens,  and  the  C02  collecting, 
gives  to  the  liquor,  when  drawn,  its  sparkling,  foamy 
appearance. 

£ager  'Seer  (Lagern,  to  lie)  is  so  called  because  it 
is  allowed  to  lie  for  months  in  a  cool  cellar,  where  it 
ripens  very  gradually.  It  is  also  fermented  much  more 
slowly  and  perfectly  than  ale  or  porter. 

Wine  is  made  from  the  juice  of  the  grape.  The  juice, 
or  mustf  as  it  is  called,  is  placed  in  vats  in  the  cellar, 
where  the  low  temperature  produces  a  slow  fermentation. 
When  all  the  sugar  is  converted  into  alcohol  and  C02,  a 
dry  wine  remains ;  when  the  fermentation  is  checked,  a 
sweet  wine  is  the  result;  and  when  bottled  while  the 
change  is  still  going  on,  a  brisk,  effervescing  wine,  like 
champagne,  is  formed.  The  flavor  or  "  bouquet "  of  wine 
is  due  to  the  slow  formation  of  a  fragrant  and  aromatic 
ether.*  (See  p.  204.)  The  tartaric  acid  of  the  grape 
gradually  separates  and  collects  on  the  sides  and  bottoms 
of  the  casks  in  a  white  incrustation — cream  of  tartar. 

A2coho2  in  3$eer,  Wine,  etc. — Alcohol  is  the 
intoxicating  principle  of  all  varieties  of  liquors,  ale,  beer, 
wine,  cider,  and  the  domestic  wines.  Ale  and  porter 
contain  from  6  to  8  per  cent,  of  alcohol ;  wine  varies  from 
7  per  cent,  in  the  light  claret  to  17  per  cent,  in  the  strong 
Port  and  Madeira ;  brandy  and  whisky  have  from  40  to 
50  per  cent. — KOSCOE. 

Ardent  Spirits.  —  When  any  fermented  liquor  is 
distilled,  the  alcohol  passes  over,  together  with  water 
and  some  fragrant  substances  which  are  condensed.  In 
this  way  brandy  is  made  from  wine ;  rum  from  fermented 

*  (Enanthic  ether,  a  liquid  with  a  powerful  odor,  which  causes  the  peculiar 
smell  of  grape- wine.— MILLEB. 


196 


ORGANIC     CHEMISTRY. 


molasses  or  cane-juice;  whiskey  from  fermented  corn, 
rye,  or  potatoes ;  and  gin  from  fermented  barley  and  rye, 
afterward  redistilled  with  juniper-berries.  The  accompa- 
nying cut  represents  an  apparatus  used  for  this  distilla- 

Fig.  71. 


A  stw. 

tion.  A  is  the  boiler,  B  the  dome,  C  a  tube  passing  into 
S,  the  condenser,  where  it  is  twisted  into  a  spiral  form 
called  the  worm,  in  which  the  vapor  from  the  boiler  is 
condensed,  and  drops  out  at  D.  (See  Philosophy,  p. 
237.) 

Alcohol  (C2H60)*  is  prepared  by  distilling  whiskey, 
and  is  sometimes  called  spirits  of  wine.  It  boils  at  173°, 
and  has  never  been  frozen  even  at  —166°  R  It  contains, 

*  Ethyl  alcohol  or  vinic  alcohol.    It  is  also  known  as  ethyl  hydrate,    (See 
Marsh-gas  Series,  p.  301.) 


FERMENTATION.  197 

when  strongest,  10  per  cent,  of  H  2  0,  which  can  be  sepa- 
rated by  adding  some  substance  like  lime,  which  has  a 
strong  affinity  for  H20.  It  is  then  called  anhydrous  or 
absolute  alcohol.  When  C2H60  is  exposed  to  the  air  the 
spirit  evaporates,  while  moisture  is  absorbed  from  the 
atmosphere.*  It  burns  without  smoke  and  with  intense 
heat,  owing  to  the  abundance  of  H  and  deficiency  of  C, 
and  is  therefore  of  great  value  in  the  arts.  It  is  also  of 
incalculable  importance  as  a  solvent  of  many  substances 
— roots,  resins,  fragrant  oils,  etc. 

JZffecls  of  Alcohol. — When  pure  it  is  a  deadly  poi- 
son. When  diluted,  as  in  the  ordinary  liquors,  it  is  stim- 
ulative and  intoxicating.  Its  influence  is  on  the  brain 
and  nervous  system ; — deadening  the  natural  affections, 
dulling  the  intellectual  operations  and  moral  instincts ; 
seeming  to  pervert  and  destroy  all  that  is  pure  and  holy 
in  man,  while  it  robs  him  of  his  highest  attribute — 
reason.  (See  Physiology,  p.  150.) 

Hither  [(C2H5)20]. — Sulphuric  Etlier  is  formed  by  the 
distillation  of  C2H60  with  H2S04.t  It  has  a  fragrant 
odor,  boils  at  about  94°,  and  burns  with  more  light  and 
smoke,  but  less  heat,  than  alcohol.  Its  vapor  is  thirty- 
seven  times  heavier  than  H,  and  can  be  poured  like  C02.| 
By  the  action  of  different  acids  on  C2H60,  other  ethers 
are  produced,  viz.,  nitric,  acetic,  butyric, §  etc. 

*  The  chemist  discovers  this  when  he  neglects  to  put  the  extinguisher  on  bis 
alcohol-lamp,  and  finds  that  he  cannot  relight  it  without  moistening  the  wick 
with  fresh  alcohol. 

t  Though  thus  named,  this  ether  contains  no  S.  It  is  known  as  ethyl  oxide. 
(See  page  202.) 

t  It  should  he  used  with  care  in  the  presence  of  a  light,  as  it  is  inflammahle  and 
becomes  explosive  when  mixed  in  proper  proportions  with  air. 

§  This  has  the  odor  of  pine-apple,  and  is  sold  as  pine-apple  oil.  The  melon 
and  strawberry  are  supposed  to  owe  a  portion  of  their  flavor  to  this  ether. 


198  ORGANIC     CHEMISTRY. 

Chloroform  (CHC13)  is  made  by  distilling  C2H60 
with  chloride  of  lime.  It  is  colorless,  volatile,  of  a  sweet 
taste,  and  should  be  free  from  any  unpleasant  odor 
when  evaporated  on  the  hand.  It  is  used  as  a  solvent  of 
I,  P,  S,  and  caoutchouc,  and  as  an  anaesthetic.  The  value 
of  ether  and  chloroform  in  alleviating  pain,  is  beyond 
estimate. 

Ch2ora2  (C2C13HO)  is  formed  by  passing  Cl  through 
absolute  alcohol.  It  is  an  oily  liquid  which  combines 
with  H20,  making  Chloral  Hydrate,  a  white,  crystalline 
substance,  much  used  to  induce  sleep.  Taken  in  proper 
quantities  it  is  entirely  safe,  and  is  exceedingly  pleasant 
in  its  influence. 

Acetic  Acid  (C2H402,  acetum,  vinegar)  forms  from 
two  to  four  per  cent,  of  common  vinegar,  whence  its 
name.  The  strongest  acetic  acid  is  known  as  the  glacial, 
since  it  crystallizes  into  an  ice-like  solid  at  63°.  It  has 
an  aromatic  taste  and  pungent  odor,  and,  after  a  time, 
blisters  the  skin. 

72  Preparation. — Vinegar  is  made  on  a 

large  scale  by  filtering  a  mixture  of  alco- 
hol and  yeast  through  a  cask  filled  with 
beech  shavings  soaked  in  vinegar.  As  the 
fermenting  alcohol  slowly  trickles  down, 
it  comes  in  close  contact  with  the  air, 
absorbing  0  so  rapidly  that  sometimes 
before  it  reaches  the  bottom  it  becomes 
Making  virxgar.  entirely  converted  into  vinegar. 

Cider  Yinegar.  — Cider  contains  some  nitrogenous 
matter,  which  acts  as  a  ferment,  by  which  the  starch  of 
the  apple  is  broken  up  into  C2H60  and  C02.  This 
makes  what  is  called  " old  cider"  By  exposure  to  the  air 


FERMENTATION.  199 

and  heat,  the  alcohol  passes  on  to  the  second  stage,  and 
the  acetic  acid  formed  produces  the  sour  taste  of  the  vin- 
egar.* 

Properties. — Acetic  acid  is  a  solvent  of  albumen,  gela- 
tin, fibrin,  etc.  Hence  it  takes  from  meat,  eggs,  oysters, 
etc.,  their  most  strengthening  constituents.  For  a  simi- 
lar reason,  vinegar  is  a  valuable  assistant  in  digesting 
such  food.  It  allays  thirst,  and  was  anciently  carried  by 
the  Roman  soldiers  in  a  little  flask  for  that  purpose. 
Sugar  added  to  vinegar  quickly  passes  to  the  second  stage 
of  fermentation,  and  increases  its  strength.  Indeed, 
vinegar  is  sometimes  made  entirely  from  sweetened  water 
and  tea-leaves,  which  act  as  a  ferment.  Vinegars  of 
commerce  are  often  sharpened  by  the  addition  of  H2S04 
and  pungent  spices,  f 

^Preserves  frequently  "  work,"  as  it  is  called,  and  then 
sour.  The  bubbles  of  gas  which  rise  to  the  surface  indi- 
cate the  alcoholic  fermentation.  If  neglected,  this  soon 
passes  to  the  acetic  stage.  It  may  be  checked  by  scald- 
ing, which  destroys  the  ferment. 

A.2de?iyde. — A  molecule  of  alcohol  absorbs  two  atoms 
of  0  from  the  air,  as  we  have  seen,  forming  acetic"  acid 
and  water.  In  this  process,  there  is  an  intermediate  step 
during  which  the  two  atoms  of  H  combine  with  one  atom 
of  0,  forming  a  molecule  of  water.  This  intermediate 


*  Mother,  in  vinegar,  is  a  fungus  (Mycoderma  aceti)  produced  by  the  decom- 
position of  the  nitrogenous  matter.  It  absorbs  O  from  the  air  and  gives  it  up  to 
the  alcohol 

t  We  can  easily  detect  these  by  evaporating  a  half-gill  in  a  saucer,  placed  over 
hot  water.  As  it  boils  down,  add  a  little  sugar,  taking  care  not  to  allow  it  to 
burn.  If  the  liquid  turns  black,  it  is  proof  of  the  presence  of  HaSO«.  As  the 
last  evaporates,  the  odor  of  cayenne  pepper,  etc.  (if  there  be  any),  can  be  readily 
distinguished. — In  England,  commercial  vinegar  is  permitted  by  law  to  have  one 
part  in  a  thousand  of  oil  of  vitriol,  as  this  ke«ps  it  from  moulding.— MJLLEB. 


ORGANIC    CHEMISTRY. 

substance  is  called  aldehyde,*  which  quickly  absorbs  a 
second  atom  of  0,  producing  acetic  acid. 


ORGANIC     RADICALS. 

A  KADICAL  is  the  root  of  a  series  of  compounds 
which  differ  from  each  other  by  a  constant  amount. 
Such  series  are  said  to  be  homologous  (homos,  same; 
logos,  proportion),  and  the  different  members  to  be  homo- 
logues  of  each  other. 

Marsh-gas  Series.—  Marsh-gas,  CH4  (page  81),  is 
the  first  member  of  a  series  of  hydrocarbons,  whose  com- 
mon difference  is  CH2.  The  symbol  CH4  maybe  written 
(CH3)H,  and  considered  as  the  hydride  of  a  group  of 
atoms  called  methyl:  hence  marsh-gas  is  called  methyl 
hydride.  Methyl  is  the  radical  of  a  series  of  compounds, 
and  plays  the  part  of  an  element  in  various  chemical 
reactions.  The  other  members  of  the  series  may  be  writ- 
ten in  the  same  way,  and  are  regarded  as  hydrides  of 
the  radicals  ethyl,  propyl,  lutyl,  etc. 

Methyl  Hydride  (Marsh-gas) CH4     =CH3,H 

Deutyl  or  Ethyl  Hydride C2H6  =C2H6,H 

Trityl  or  Propyl  Hydride C3H8  =C3H7,H 

Tetryl  or  Butyl  Hydride C4H x 0=±C4H9,H 

Pentyl  or  Amyl  Hydride C5H12=C6H,  ,,H 

Hexyl  Hydride C6H14=C6H13,H 

Heptyl  Hydride C7H, 6=C7H , 6,H 

Octyl  Hydride .C8H18=C8H17,H 

Nonyl  Hydride ...C9H20=C9H19,H 

etc.  .  etc. 

*  The  odor  of  aldehyde  may  be  obtained  by  holding  a  red-hot  coil  of  Pt  wire 
in  a  goblet  containing  a  few  drops  of  alcohol.    This  experiment,  showing  the 


ORGANIC    RADICALS.  %01 

The  A2co?io2s. — Common  alcohol,  C2H60,  may  be 
written  C2H5,HO,  which  is  the  hydrate  of  the  radical 
ethyl ;  hence  it  is  known  as  the  ethyl  hydrate.  Each  of 
the  other  radicals  just  named  has  its  hydrate  or  alcohol. 
In  some  cases  it  has  not  yet  been  separated,  though  its 
symbol  is  known,  and  the  body  is  believed  to  exist.  The 
series  has  been  continued  as  high  as  melyl  alcohol, 
C30H620. 

Boiling 
Point. 

Methyl  Alcohol  (wood-spirit)  *. . . . CH40      =CH 3,HO  ....  66°  C 

Ethyl  Alcohol C2H6O     =  C2H5,HO  ....  78° 

Propyl  Alcohol C3H8O     =C3H7,HO  ....  96° 

Butyl  Alcohol C4H10O  =  C4H9,HO  ....109° 

Amyl  Alcohol  (fusel  oil) f C5H120  =C5HM,HO  ....132° 

Hexyl  Alcohol C6H14O  =  C6H13,HO  ....150° 

Heptyl  Alcohol C7H16O  =  C7H16,HO  ....164° 

C8H180  =  C8H17,HO  .... 

C9H200  =  C9H19,HO  .... 

Decatyl  Alcohol C10H22O-C10H2  ,,HO. . .  .212° 

Aldehydes  and  Acids.—  Ethyl,  or  common  alco- 
hol, by  an  oxidizing  agent  loses  two  atoms  of  H,  and  is 
changed,  as  we  have  seen,  to  C2H40,  or  ethyl  aldehyde. 
This  can  be  further  oxidized  into  acetic  acid.  Each  of 


formation  of  aldehyde  from  alcohol,  may  be  very  profitably  followed  by  another, 
illustrating  the  change  of  alcohol  into  acetic  acid.  Place  a  little  platinum  black 
in  a  watch  crystal,  near  a  small  cup  of  alcohol.  Cover  them  both  with  a  glass 
receiver,  and  set  them  in  the  sunlight.  Soon  a  mist  will  gather,  and  tiny  streams 
of  the  condensed  vapor  of  acetic  acid  will  collect  and  run  down  the  sides  of  the 
glass.  Fresh  air  must  be  occasionally  admitted  to  oxidize  the  alcohol. 

*  Methyl  alcohol  is  very  like  ethyl  alcohol,  and  is  used  for  similar  purposes,  as 
dissolving  resins,  etc.  Methylated  spirit  is  ethyl  alcohol  with  about  10  per  cent, 
of  wood  spirit,  which  does  not  injure  it  for  many  uses  to  which  ordinary  alcohol 
is  applied. 

t  This  is  formed  in  distilling  whiskey  from  potatoes.  It  is  present  in  common 
CaH6O,  giving  a  slightly  unpleasant  odor  when  it  evaporates  from  the  hand. 
It  is  extremely  poisonous,  and  as  it  is  often  contained  in  liquors,  must  greatly 
increase  their  destructive  and  intoxicating  properties. 


ORGANIC     CHEMISTRY. 

the  alcohols  can  thus  be  oxidized,  and  will  yield  an  alde- 
hyde and  an  acid.  The  following  is  a  list  which  is  more 
complete  even  than  that  of  the  alcohols  themselves : 

Source. 

Formic  Acid* CH202       Red  ants,  oxalic  acid,  etc. 

Acetic  Acid C2H4O2     Alcohol,     distillation    of 

Propionic  Acid C .,  H  6  O  2     Glycerin.  [wood. 

Butyric  Acid C4H802     Butter. 

Valerianic  Acid C5H I002   Valerian  root. 

Caproic Acid C6H , 203   .Butter. 

(Enanthylic  Acid C7  H ,  4O2   Castor  oil. 

Capric  Acid C8H  ,  602   Butter. 

Pelargonic  Acid C9H,803   Geranium  leaves. 

Rutic  Acid C ,  nH20O2 .Oil  of  rue,  butter. 

Laurie  Acid C12H2402 .  .Berries  of  bay  tree. 

Myristic  Acid Cj 4H28O2 Nutmeg  butter. 

Palmitic  Acid  f C,  6H:J2O2 Palm  oil. 

Margaric  Acid f C,  7H34O2 Animal  fats. 

StearicAcidf C18H36O2 " 

Arachic  Acid C2 „  H  4 002 Butter. 

Behenic  Acid C22H44O2 

Hysenic  Acid C26H60O3 

Cerotic  Acid C37H5402 Beeswax. 

Melissic  Acid C30H60O2 " 

The  IZthers. — Common  ether  is  formed,  as  we  have 
seen,  from  ethyl  alcohol  by  the  action  of  h^SO^.;  and  its 
symbol,  (C2H5)20,  represents  that  it  is  considered  as 
ethyl  oxide.  Each  of  the  other  alcohols  \  has  its  ether — 
the  oxide  of  its  radical.  Thus, 

*  Formic  acid,  which  was  found  in  red  ants  (Formica  rufa),  is  a  fiery,  pungent 
fluid,  which  hlisters  the  skin.  It  is  made  from  methyl  alcohol,  as  acetic  acid 
is  from  common  or  ethyl  alcohol. 

t  Palmitic,  margaric,  and  stearic  acids,  are  known  as  the  fatty  acids  (see 
page  218),  and  are  of  great  value  in  the  arts. 

$  The  term  alcohol  is  now  applied  to  those  neutral  compounds  of  H,  C,  and  O, 
which  react  upon  the  acids,  eliminating  water  and  forming  ethers. 


ORGANIC    RADICALS. 

Methyl  Ether C2H6O     =(CH3)2O 

Ethyl  Ether C4H 10O  =(C2H6)2O 

Propyl  Ether .C6H, 4O  =(C3H7)2O 

Butyl  Ether C8H,8O  =(C4H9)2O 

Amyl  Ether C10Ha20=(C6H11)20 

Compound  Ammonias* — Each  alcohol  also  forms 
a  series  of  compound  ammonias.     H3N  may  be  written 

ij   \ 

thus,  H  t  N?  and  one  or  more  atoms  of  H  may  be  replaced 
H  ) 

by  a  radical.    In  the  ethyl  series,  for  example,  we  haye 
V  i  N,  or  ethylamine;   C°H!  I  N,  diethylamine  ;  C^H!  i  N, 

triethylamine.     These  ammonias  closely  resemble  com- 
mon ammonia,  neutralize  acids,  produce  white  clouds  with 
HC1,  and  form  crystallizable  salts;  though  they  steadily 
rise  in  their  boiling  point. 
Salts  of  the  Radicals.  —  The  symbol  for  water 

may  be  written  thus,  H  [  o ;  caustic  potash,  *  [  o ;    and 

H   )  H  ) 

ethyl  alcohol  after  the  same  type,  Ca"4  o.    As  by  adding 

H    ) 

HC1  to  KHO  we  obtain  KC1  and  H20,  so  we  can  form  the 
chlorides,  iodides,  bromides,  etc.,  of  all  the  radicals  of  the 
marsh-gas  series  by  treating  the  alcohol  with  the  proper 
acid.  Ethyl,  for  example,  thus  furnishes  compounds 
analogous  to  the  potassium  salts. 

1.  Potassium  nitrate NQ    \  0. 

1.  Ethyl  nitrate  (Ethyl-nitric  ether) j^6  \  0. 

K  ) 

2.  Hydrogen-potaasium-sulphate l_j  £  S04. 

2.  Hydrogen- ethyl-sulphate  (Sulphuric  ether*) . Cz  Jj 5  i  SO4 . 


*  This,  rather  than  ethyl  oxide  (see  p.  197),  is  the  true  sulphuric  ether;  com- 


ORGANIC     CHEMISTRY. 

3.  Potassium  sulphate £  I  S04. 

3.  Ethyl  sulphate  (Ethyl-sulphuric  ether) £*£j5  I  S04. 

4.  Potassium  acetate C* ^ 3°  I  O. 

4.  Ethyl  acetate  (Ethyl-acetic  ether) C*  H3°  1  °' 

The  salts  of  the  radicals  are  often  termed  compound 
ethers,  to  distinguish  them  from  the  simple  ethers,  which 
are  the  oxides.  They  are  extensively  sold  as  flavoring 
extracts  for  the  use  of  confectioners  and  cooks.  The 
essence  of  jargonelle  pear  is  an  alcoholic  solution  of  amyl 
acetate ;  apple  oil,  of  amyl  valerianate ;  pine  apple,  of 
ethyl  butyrate. 

There  are  many  series  of  organic  bodies,  of  which  those 
given  are  merely  illustrations.  The  various  changes 
which  they  can  undergo  indicate  what  a  wide  field  lies 
open  for  discovery,  and  the  multitude  of  possible  organic 
compounds. 


DESTRUCTIVE    DISTILLATION. 

1.  DECAY. — When  wood  decays  slowly  in  the  open 
air,  the  H  passes  off,  the  proportion  of  C  increases,  the 
color  darkens,  and  a  black  carbonaceous  mass  remains, 
called  humus.  This  is  of  great  value  to  the  soil,  as  its 
pores  absorb  H3N,  which,  together  with  C02  produced  by 

pare  its  formula  with  that  of  sulphuric  acid,  showing  it  to  be  a  true  salt  as  de- 
fined in  the  note  on  page  23. 


DESTRUCTIVE    DISTILLATION.  205 

its  decay,  is  furnished  to  the  growing  plant.  When  the 
supply  of  humus  is  exhausted  from  the  soil,  we  restore 
it  by  adding  straw,  etc.,  and  by  plowing  in  green 
crops. 

2.  DISTILLATION.— When  hard  wood,  as  beech  or 
oak,  is  heated  to  a  high  temperature,  with  no  0  present, 
or  an  imperfect  supply,  it  is  decomposed ;  the  charcoal 
remains,  while  a  large  number  of  products  are  formed, 
among  which  are  H,  CO,  C02,  H20,  CH4,  methyl  alcohol, 
acetic  or  pyroligneous  acid,  creosote,  paraffine,  tar,  etc. 

^Pyroligneous  Acid  (wood- vinegar)  is  the  crude 
acetic  acid.  It  is  used  in  making  the  acetates  from  which 
the  pure  acid  is  obtained  by  the  action  of  a  stronger  acid, 
as  H2S04. 

Creosote  (flesh-preserver)  is  a  colorless,  poisonous 
liquid,  with  a  flavor  of  burnt  wood.*  It  has  powerful 
antiseptic  properties.  _It  imparts  to  smoke  a  character- 
istic odor,  renders  it  irritating  to  the  eyes,  and  also  gives 
to  it  -the  power  which  it  possesses  of  curing  hams, 
beef,  etc. 

*Paraffine  (parum,  little;  qffinis,  affinity),  so  called 
because  the  acids  and  bases  have  no  effect  upon  it,  is  a 
hard,  white,  tasteless  solid,  resembling  spermaceti.  It 
forms  beautiful  candles,  which  look  and  burn  like  the 
finest  of  wax.  It  is  a  product  of  the  rectification  of 
beech-wood  tar,  but  the  paraffine  of  commerce  is  now 
obtained  from  petroleum. 

Tar  is  made,  like  charcoal,  by  burning  heaps  of  wood 
under  a  covering  of  earth  which  excludes  the  air :  an 
imperfect  combustion  ensues,  the  resinous  matter  exudes, 

*  Much  of  that  which  is  sold  as  creosote  is  carbolic  acid.    (See  page  206.) 


206  ORGANIC     CHEMISTRY. 

and,  trickling  down,  runs  into  a  reservoir  below.  On  the 
extensive  pine-barrens  of  North  Carolina  the  tar  of  com- 
merce is  principally  produced. 

COAL-TAR  is  formed  in  the  process  of  making  coal-gas. 
(See  p.  81.)  It  was  formerly  thought  valueless,  but  is 
now  used  for  a  great  variety  of  purposes.  On  distillation 
it  yields,  among  other  products,  ammonium  salts  (see  pp. 
83, 135),  carbolic  acid,  benzole,  coal-naphtha,  and  dead-oil. 

Carbolic  Acid  (Phenic  Acid,*  C<;H60)  is  noted  for 
its  antiseptic  and  disinfecting  properties.  By  heating  it 
with  HN03,  picric  acid  is  formed.  This  colors  a  rich 
yellow,  and  is  a  very  popular  silk  dye.  The  picrates  are 
yellow,  explosive  salts.  Potassium  picrate  is  used  in 
making  certain  kinds  of  gunpowder. 

^Benzole  f  is  a  light  oil  used  as  a  solvent  of  gutta- 
percha,  caoutchouc,  and  wax ;  for  removing  grease-spots ; 
as  a  burning-fluid,  etc.  Its  ready  inflammability  makes  it 
an  exceedingly  dangerous  article.  A  current  of  air  passed 
through  benzole,  as  well  as  through  any  of  the  other 
light  hydrocarbons,  will  absorb  so  much  vapor  that  it 
may  be  burned  as  an  illuminating  gas.  Machines  for 
lighting  houses,  etc.,  are  based  upon  this  principle. 

Nilro-jBenzo2e  is  formed  by  treating  benzole  with 
HN03.  It  is  a  heavy,  oily  liquid,  with  an  odor  like  that 
of  bitter  almonds.  It  is  chiefly  valuable,  however,  as  the 
source  of  aniline, J  from  which  are  prepared  the  celebrated 

*  The  formula  for  carbolic  acid  is  CBHaO,  and  may  be  written  as  C6HS,HO. 
The  acid  may  then  be  considered  as  the  hydrate  of  the  radical  phenyl,  and  hence 
is  sometimes  called  phenyl  alcohol.  Phenyl  is  the  radical  of  a  series  of  hydro- 
carbons, abundant  in  the  coal-oils. 

t  Benzole  was  so  named  because  of  its  abundance  in  benzoic  acid.  It  was  for- 
merly sold  as  benzine,  but  a  cheaper  coal-oil  has  now  taken  its  place. 

t  In  1856,  Mr.  Perkin,  while  experimenting  with  aniline  in  hopes  of  making 
quinine,  treated  it  with  potassium  bichromate.  He  did  not  succee'd  in  his 


DESTRUCTIVE    DISTILLATION.  207 

coal-tar  dyes. — Example :  mauve,  magenta,  etc.  Who  but 
a  chemist  would  have  searched  in  black,  sticky  coal-tar 
for  these  rainbow-tints,  the  stored-up  sunshine  of  the 
carboniferous  age ! 

Naphtha  is  a  volatile,  limpid  oil,  with  a  peculiar  odor 
and  generally  a  light  straw  color.  It  is  composed  of  sev- 
eral hydrocarbons  and  is  very  inflammable.  Naphthaline 


attempt,  but  lie  obtained  a  beautiful  purple  dye,  which  was  soon  introduced  to 
commerce  under  the  name  of  mauve.  A  host  of  imitators  at  once  sought  to  obtain 
the  color  without  using  potassium  bichromate.  As  the  only  use  of  the  latter  was 
to  oxidize  the  aniline,  they  reasoned  that  they  might  use  any  other  oxidizing 
agent.  Arsenic,  among  other  substances,  was  tried,  but  instead  of  a  purple  the 
red  known  as  magenta  was  the  result.  The  coloring  matter,  however,  does  not 
contain  any  arsenic ;  being  a  salt  of  a  base  called  rosaniline.  Rosaniline  itself  is 
colorless,  and  reveals  its  magnificent  tints  only  in  its  compounds.  "  The  crystals 
of  its  salts  exhibit  by  reflected  light  the  metallic  green  color  of  beetles'  wings, 
but  are  of  a  deep  red  color  when  seen  by  transmitted  light."  Magenta  is  manu- 
factured on  an  enormous  scale  in  England,  more  as  a  substance  from  which  to 
obtain  other  dyes  than  for  direct  use  in  dyeing.  A  single  firm  produces  twelve 
tons  a  week.  The  quantity  of  magenta  furnished  by  one  hundred  pounds  of  coal, 
is  very  small ;  but  this  is  compensated  for  by  its  intense  coloring  power,  since  it 
will  dye  a  quantity  of  wool  nearly  equal  in  weight  to  the  coal.  In  making 
magenta  on  the  large  scale  there  are  considerable  quantities  of  residual  products. 
These  of  course  have  been  examined  with  a  view  to  further  profit,  and  the  result 
has  been  the  discovery  of  a  beautiful  orange  color  called  phosphine.  This  is  much 
used  to  produce  scarlet,  by  first  dyeing  the  silk  or  wool  with  magenta,  and  then 
passing  it  through  a  bath  of  phosphine.  By  treating  magenta  with  aniline,  a 
beautiful  blue  is  obtained.  This  is  insoluble  in  water,  but  is  rendered  soluble 
exactly  as  indigo  is,  by  treating  it  with  sulphuric  acid.  Another  curious  dye 
formed  from  aniline  is  known  as  Nicfiolsori >s  blue.  This  is  completely  decolor- 
ized by  alkalies,  and  the  color  is  restored  by  acids.  In  dyeing  with  it,  the  silk  01 
wool  is  first  immersed  in  a  colorless  solution  of  the  dye,  and  then  dipped  into 
dilute  sulphuric  acid,  when  the  blue  is  at  once  developed.  If  magenta  is  heated 
with  iodide  of  ethyl  or  methyl,  an  excess  of  the  iodide  being  employed,  a  most 
beautiful  green  is  the  result.  If,  however,  this  green  is  heated  sufficiently  to 
drive  off  the  excess  of  iodide,  a  violet  color  is  the  result ;  so  that  it  will  not  do  for 
ladies  wearing  dresses  dyed  with  this  green  to  sit  too  near  the  fire.  After  all  the 
coloring  matter  has  been  extracted  from  the  aniline,  a  residue  remains  which 
has  an  intense  black  color  and  is  largely  used  for  making  printing  ink.  Very  few 
of  the  aniline  colors  when  in  powder  give  a  person  any  idea  of  the  color  which 
they  will  produce  when  moistened.  Magenta,  for  instance,  when  dry,  is  a  beau- 
tiful green  with  a  bronze-like  lustre.  It  is  a  pretty  experiment  to  coat  a  sheet  of 
glass  with  one  of  these  colors,  which  is  readily  done  by  dissolving  in  alcohol 
(HofmamVs  violet  being  the  best)  and  allowing  a  film  of  it  to  evaporate  on  the 
glass.  When  seen  by  transmitted  light  it  is  of  a  beautiful  violet,  but  with  reflect- 
ed light  it  displays  a  tint  rivalling  in  brilliancy  the  tail  of  a  peacock.  —Boston 
Journal  of  Chemistry. 


ORGANIC     CHEMISTRY. 

is  a  crystalline  solid  occurring  in  beautiful  pearly  scales. 
It  is  especially  abundant  in  dead-oil,  and  may  be  formed 
by  passing  olefiant  gas  or  benzole  through  red-hot  tubes. 
Anthracene  accompanies  naphthaline  in  the  latter  part  of 
its  distillation.  It  is  also  a  white  solid.  It  is  of  interest 
since  the  coloring  principle  of  madder — alizarine— has 
been  made  from  it. 

%)ead-  Oi2  is  used  for  preserving  timber ;  as  a  cement 
for  roofs  and  walls ;  for  oiling  machinery,  etc. 

PETROLEUM  (petra,  a  rock;  oleum,  oil)  is  probably 
the  product  of  the  distillation  of  organic  matter  beneath 
the  surface  of  the  earth.  It  is  not  always  connected 
with  coal,  as  it  is  often  found  outside  the  coal-measures, 
as  in  New  York  and  Canada.  The  distillation  must 
have  taken  place  at  a  much  greater  depth  than  that  at 
which  the  oil  is  now  found,  as  it  would  naturally  rise 
through  the  fissures  of  the  rock  and  gather  in  the  cavities 
above.  Sometimes  the  oil  has  collected  on  the  surface  of 
subterranean  pools  of  salt-water,  so  that  after  a  time  the 
oil  is  exhausted,  and  salt-water  only  is  pumped  up ;  or  if 
the  well  strikes  the  lower  part  of  the  cavity,  the  water 
will  first  be  pumped  and  afterward  the  oil.  The  crude 
oil  from  the  well  is  purified  by  distillation.  That  which 
passes  over  at  the  lowest  temperature  is  called  naph- 
tha :  as  the  heat  is  increased,  there  passes  off  next  kero- 
sene oil  *  for  illumination,  and  lastly  lubricating  oil  The 


*  Kerosene  accidents  generally  rise  from  the  presence  of  naphtha.  This  is  a 
cheap,  light,  dangerous  oil.  Its  vapor,  however,  is  not  explosive  unless  mixed 
with  air.  While  a  lamp,  which  contains  adulterated  kerosene,  is  burning  quietly 
there  is  no  danger.  The  vapor  rises  from  the  oil,  fills  the  empty  space  in  the 
lamp,  hut  being  unmixed  with  air  cannot  explode.  Let,  however,  a  draught  of 
cold  air  strike  it,  or  carry  it  into  a  cold  room— instantly  the  vapor  will  be  con- 
densed, the  air  will  rush  in,  and  a  dangerous  mixture  be  formed.  Or  when  the 
light  is  extinguished  at  night  the  vapor  will  cool,  air  pass  in,  and  a  mixture  be 


DESTRUCTIVE    DISTILLATION.  209 

kerosene  is  deodorized  and  decolorized  by  the  use  of 
H2S04  and  other  chemicals,  which  are  stirred  in  the  oil, 
after  which  it  is  redistilled. 

Bitumen  or  Asphattum.  —  Petroleum  and  naph- 
tha, flowing  from  the  ground,  have  formed  beds  of  bitu- 
men in  various  parts  of  the  world.  This  change  is  caused 
by  a  gradual  oxidation  and  hardening,  as  turpentine 
changes  to  rosin.  Tar  Lake  is  situated  on  the  island  of 
Trinidad.  It  is  nearly  three  miles  in  circumference. 
The  bitumen  is  used  for  the  same  purposes  as  pitch, 
which  it  closely  resembles.  Near  the  shore  it  is  hard 
and  compact,  except  in  hot  weather,  when  it  becomes 
sticky.  At  the  centre  it  is  soft,  and  fresh  bitumen  boils 
up  to  the  surface.  Asphaltum  is  found  in  immense 
quantities  in  California  and  in  Canada.  It  is  a  natural 
cement  for  laying  stone  or  brick.  It  was  used  in  build- 
ing the  walls  of  Babylon,  for  which  purpose  it  was 
gathered  from  the  fountain  of  Is  on  the  banks  of  the 
Euphrates.  It  was  a  prominent  ingredient  in  the  "  Greek 
Fire,"  so  much  used  by  the  nations  of  Eastern  Europe  in 
their  naval  wars,  even  as  late  as  the  fourteenth  century. 
This  consisted  of  bitumen,  sulphur,  and  pitch,  and  was 
thrown  through  long,  copper  tubes,  from  hideous  figures 
erected  on  the  prow  of  the  vessel.  Bitumen  is  used  in 
making  the  famous  promenades  of  the  Boulevards  in  Paris. 

produced  which  will  be  ready  to  explode  when  the  lamp  is  relighted.  Kerosene  of 
the  legal  standard  is  no  more  explosive  than  water,  and  will  even  extinguish  a 
flame  applied  to  it  at  the  ordinary  temperature.  Dr.  Nichols  gives  the  following 
simple  test :  Fitt  a  bowl  partly  full  of  hot  water.  Insert  a  thermometer,  and  add 
cold  water  until  the  temperature  is  110°  F.  Then  pour  into  the  bowl  a  spoonful  of 
kerosene  and  apply  a  lighted  match.  If  it  takes  jlre  the  oil  contains  naphtha  and  is 
dangerous  ;  if  not,  the  kerosene  may  be  used  with  perfect  safety. 


210  ORGANIC     CHEMISTRY. 


THE    ORGANIC    ACIDS. 

THERE  are  many  vegetable  acids  found  native  in  plants 
— generally,  however,  combined  with  some  base. 

Oxalic  Acid  (C2H204)  is  familiar  in  the  sour  taste 
of  rhubarb,  sorrel,  etc.  In  these  plants  the  acid  is  com- 
bined with  K  and  Ca.  It  may  be  prepared  by  the  action 
of  HN03  on  sugar.*  It  is  a  potent  poison.  The  antidote 
is  powdered  magnesia,  or  chalk,  stirred  in  H20.  It  is  a 
test  of  lime,  forming  a  delicate  white  precipitate  of  cal- 
cium oxalate.  A  solution  of  oxalic  acid  is  much  used 
to  remove  ink  stains,  and  is  often  sold  for  this  purpose 
under  the  deceptive  name  of  "  salts  of  lemon."  The  acid 
unites  with  the  Fe  of  the  ink,  and  the  iron  oxalate  thus 
made  is  soluble  in  H20.  It  should  be  washed  out  imme- 
diately, as  it  will  corrode  the  cloth. 

Tartaric  Acid  (C4H606)  exists  in  many  fruits, 
principally  in  the  grape,  combined  with  K  as  hydrogen 
potassium  tartrate  ("bitartrate  of  potash").  This  settles 
during  the  fermentation  of  wine  (see  p.  195),  and  when 
purified  is  called  cream  of  tartar,  from  which  tartaric  acid 
is  made.  It  forms  transparent  crystals  of  a  pleasant  acid 
taste,  which  are  permanent  in  the  air.  Its  aqueous  solu- 
tion gradually  becomes  mouldy  and  turns  into  acetic  acid. 
Tartar  emetic  is  an  antimony  potassium  tartrate.  Ro- 
chelle  salt  is  a  sodium  potassium  tartrate ;  it  is  commonly 
used  in  medicine  in  the  form  of  Seidlitz  powders.  These 
are  contained  in  a  blue  and  a  white  paper.  The  former 

*  Oxalic  acid  is  made  on  a  large  scale  from  sawdust,  soda,  and  caustic  potash. 
The  woody  fibre  is  resolved  into  oxalic  acid,  which  combines  with  the  bases, 
forming  sodium  and  potassium  oxalates.  From  these  the  acid  is  readily  ob- 
tained. Sawdust  will  yield  more  than  half  its  weight  of  crystals  of  this  salt. 


THE     ORGANIC    ACIDS. 

holds  120  grains  of  Kochelle  salt,  and  40  grains  of  bicar- 
bonate of  soda ;  the  latter  35  grains  of  tartaric  acid.  They 
are  dissolved  in  separate  goblets.  The  one  containing 
the  acid  is  emptied  into  the  other,  when  the  C02  is  set 
free,  producing  a  violent  effervescence  and  disguising  the 
taste  of  the  medicine. 

Malic  Acid  (C4H605)  occurs  abundantly  in  most 
acid  fruits,  particularly  in  unripe  apples,  whence  its  name 
from  malum,  an  apple.  Citric  acid  (citrus,  a  lemon),  the 
acid  of  the  lemon,  lime,  etc.,  is  often  found  associated 
with  it,  as  in  the  gooseberry,  raspberry,  and  strawberry. 
Citric  acid  is  used  in  medicine  as  magnesium  citrate. 

Tannic  Acid  {tannin  (C27H220,7)  ]  is  found  in  the 
leaf  and  bark  of  trees.* — Example :  Oak,  hemlock.  Nut- 
galls  are  excrescences  which  are  formed  by  the  puncture 
of  an  insect  on  the  leaves  of  a  certain  species  of  oak. 
Tannin  has  an  astringent  taste,  is  soluble  in  water,  and 
hardens  albuminous  substances,  as  gelatine. 

Tanning. —  After  the  hair  has  been  removed  from 
the  skins  by  milk  of  lime,  they  are  soaked  for  days,  the 
best  kinds  for  months,  in  vats  full  of  water  and  ground 
oak  or  hemlock  bark  (tan-bark).  The  tannic  acid  of  the 
bark  is  dissolved,  and  entering  the  pores  of  the  skin, 
unites  with  the  gelatine,  forming  a  hard,  insoluble  com- 
pound which  is  the  basis  of  leather.  Leather  is  black- 
ened by  washing  the  hide  on  one  side  with  a  solution  of 
copperas.  The  tannic  acid  unites  with  the  iron,  forming 
a  tannate  of  iron — an  ink.  In  the  same  way,  drops  of 
tea  on  a  knife-blade  stain  it  black. 

*  This  astringent  principle  is  widely  diffused.  There  are  several  compounds 
which  possess  similar  properties,  yet  differ  in  chemical  composition.  The  tan- 
nin of  the  oak  is  called  quercitannic  add;  that  of  nut-galls,  gallotannic  acid; 
that  of  tea,  theitannic,  and  that  of  coffee,  caffeotannic  acid. 


ORGANIC    CHEMISTRY. 

Info  is  made  by  adding  a  solution  of  nut-galls  to  one 
of  copperas.  The  iron  tannate  thus  formed  has  a  pale 
blue-black  color,  as  in  the  best  writing-fluids ;  by  expos- 
ure to  the  air,  the  Fe  absorbs  more  0,  the  ink  darkening 
in  color  until  it  is  a  deep  black.  Gum  is  added  to  thicken 
and  regulate  the  flow  of  the  fluid  from  the  pen.  Creo- 
sote or  corrosive  sublimate  is  used  to  prevent  mouldiness. 
Steel  pens  are  corroded  by  the  free  H2S04  contained  in 
the  ink,  but  gold  pens  are  not  affected  by  it.* 

Gallic  Acid  (C7H605)  is  associated  with  tannin  in 
nut-galls,  and  can  be  formed  from  tannic  acid.  Pyrogal- 
lic  acid  can  be  obtained  by  the  sublimation  of  gallic  or 
gallotannic  acid.  It  is  extensively  used  in  photography 
for  the  purpose  of  developing  the  latent  image  in  the 
collodion  film  after  exposure  to  the  action  of  the  light. 
(See  p.  167.) 


THE    ORGANIC    BASES. 

THE  organic  bases,  or  alkaloids,  as  they  are  called,  are 
the  bases  of  true  salts  found  in  plants.  They  dissolve 
slightly  in  H20,  but  freely  in  alcohol.  They  have  a  bit- 
ter taste,  and  rank  among  the  most  fearful  poisons  and 
valuable  medicines.  All  the  alkaloids  contain  N.f 


*  The  following  is  an  instructive  experiment,  illustrating  the  manner  of  mak- 
ing ink,  of  removing  stains  with  oxalic  acid,  and  also  the  relative  strength  of  the 
acids  and  alkalies.  Take  a  large  test-tube,  and  add  the  following  reagents  in 
solution,  cautiously,  drop  by  drop,  watching  the  result  and  explaining  the  reac- 
tions :  1,  iron  sulphate  (copperas) ;  2,  tannic  acid  (tannin) ;  3,  oxalic  acid ;  4, 
sodium  carbonate  (sal-soda) ;  5,  hydrochloric  acid  (muriatic)  •  6,  ammonia 
(hartshorn) ;  7,  nitric  acid  (aquafortis) ;  8,  caustic  potash ;  9,  sulphuric  acid  (oU 
of  vitriol). 

t  A  convenient  antidote  is  tannin,  which  forms  with  nearly  all  of  them  insolu- 
ble curdy  tannates— MILLER.  Any  liquid  containing  it  is  of  value— as  strong. 


THE     ORGANIC    BASES. 

Opium  is  the  dried  juice  of  the  poppy  plant,  which  is 
extensively  cultivated  in  Turkey  for  the  sake  of  this  pro- 
duct. Workmen  pass  along  the  rows  soon  after  the 
flowers  have  fallen  off,  cutting  slightly  each  capsule. 
From  these  incisions  a  milky  juice  exudes  and  collects  in 
little  tears.  These  are  gathered  and  wrapped  in  leaves 
for  the  market.  Opium  contains  six  different  alkaloids 
in  combination  with  a  single  acid.  In  small  doses,  opium 
is  a  sedative  medicine ;  in  larger  ones,  a  narcotic  poison. 
Laudanum  is  the  tincture  of  opium;  and  paregoric,  a 
camphorated  tincture  flavored  with  aromatics. 

Opium-eating '.  —  Opium  produces  a  powerful  influ- 
ence on  the  nervous  system.  It  stimulates  the  brain  and 
excites  the  imagination  to  a  wonderful  pitch  of  intensity. 
The  dreams  of  the  opium-eater  are  said  to  be  vivid  and 
fantastic  beyond  description.  The  dose  must,  however, 
be  gradually  increased  to  repeat  the  effect,  and  the  result 
is  most  disastrous.  The  nervous  system  becomes  de- 
ranged, and  no  relief  can  be  secured  save  by  a  fresh 
resort  to  this  baneful  drug.*  Labor  becomes  irksome, 

green  tea.    This  is  also  of  use  as  it  tends  to  keep  the  patient  awake,  the  great 
necessity  in  the  case  of  a  narcotic  poison. 

*  In  time,  the  whole  system  becomes  so  impregnated  with  it  that  additional 
doses  utterly  fail  to  produce  the  delightful  effect  which  at  first  so  fascinated  the 
victim.  Then,  while  combining  with  the  nerves,  it  set  free  a  vast  amount  of 
vitality  and  force,  but  now  it  has  satisfied  itself.  The  subtle  alkaloid  has 
worked  its  way  into  the  tissues  and  coatings  of  his  entire  internal  organism.  If, 
resolutely,  he  summons  his  enfeebled  will,  and  commences  the  conflict,  an  agony 
of  endurance,  which  defies  all  description,  is  before  him.  The  whole  body  must 
be  reorganized,  and,  atom  by  atom,  the  life-energy  of  the  man  must  drag  out  of 
the  flesh  and  blood  the  fearful  poison.  If,  too  weak  to  attempt  so  terrible  a 
straggle,  he  continues  the  use  of  the  fatal  drug,  he  moves  on  directly  to  one  fate, 
the  opium-eater's  grave.  Paregoric,  laudanum,  morphine,  and  the  different  prep- 
arations of  opium  are  in  almost  every  case  taken  first  as  a  sedative  from  pain  or 
fatiguing  labor,  with  no  thought  of  becoming  addicted  to  their  use.  But  so 
insinuating  is  it  that  the  victim  forms  the  habit  ere  he  is  aware,  and  only  knows 
he  is  a  slave  when  for  some  reason  he  attempts  to  cease  the  customary  dose. 
No  person  can  be  too  careful  in  the  use  of  a  narcotic  whose  influence  is  liable  to 
become  so  destructive. 


814  ORGANIC     CHEMISTRY. 

ordinary  food  distasteful,  and  racking  pains  torment  the 
body. 

Morphine  (Morpheus,  the  god  of  sleep)  is  one  of  the 
alkaloid  bases  of  opium,  and  like  it  is  used  to  alleviate 
pain  and  produce  sleep.  It  is  usually  given  as  a  .sulphate 
or  chloride. 

Quinine  is  prepared  from  Peruvian  bark.  A  tincture 
of  the  bark,  or  sulphate  of  quinia,  is  employed  in  medi- 
cine in  cases  of  fever  and  ague  and  other  periodic  dis- 
eases, and  also  as  a  tonic. 

Nicotine  is  the  active  principle  of  the  tobacco  plant, 
of  which  it  forms  from  2  to  8  per  cent.  It  is  volatile, 
and  passes  off  in  the  smoke.  A  drop  will  kill  a  large  dog. 
It  probably  produces  many  of  the  ill  effects  which  follow 
the  use  of  tobacco. 

Strycfmine  is  prepared  from  the  nux  vomica  and  the 
St.  Ignatius's  bean.  It  is  also  a  constituent  of  the  cele- 
brated upas  poison.*  "  It  is  so  intensely  bitter  that  one 
grain  will  impart  a  flavor  to  twenty-five  gallons  of  water. 
One-thirtieth  of  a  grain  has  killed  a  dog  in  thirty 
seconds,  while  half  a  grain  is  fatal  to  man." 

The  Chromatic  Test,  as  it  is  called,  consists  in  plac- 
ing on  a  clean  porcelain  plate  a  drop  of  the  suspected 
liquid,  a  drop  of  H2S04,  and  a  crystal  of  potassium 
bichromate.  Mix  the  three  very  slowly  with  a  clean  glass 
rod.  If  there  be  any  strychnine  present,  it  will  change 
the  color  into  a  beautiful  violet  tint,  passing  into  a  pale 
rose.f — MILLER. 

*  "The  'woorara,'  with  which  the  South  American  Indians  poison  their 
arrows,  is  a  variety  of  strychnine.  This  is  so  deadly  that  the  scratch  of  a  needle 
dipped  in  it  will  produce  death ;  yet  it  may  he  swallowed  with  impunity. "— 
MILLER. 

t  Arsenic  was  once  in  fiavor  with  the  poisoner,  but  Marsh's  test  infallibly  re- 


THE     ORGANIC    BASES.  %15 

Caffeine  and  Tfieine  constitute  the  active  prin- 
ciple of  tea  *  and  coffee,  and  are  isomeric.  They  crystal- 
lize in  long,  flexible,  silky  needles.  In  addition,  tea  con- 
tains from  13  to  18  per  cent,  of  a  form  of  tannin  (see  p. 
211,  note),  about  15  per  cent,  of  a  nitrogenous  substance 
allied  to  caseine,f  and  a  volatile  oil  which  gives  to  it  its 
aromatic  odor  and  taste.  Coffee  contains  about  14  per 
cent,  of  a  fixed  oil,  and  also  an  essential  oil  which  is 
developed  in  roasting,  and  is  very  volatile,  so  that  it 
will  soon  escape  unless  the  coffee  be  kept  tightly  cov- 
ered. 

veals  its  presence  in  the  body  of  the  victim,  even  after  many  years  have  elapsed. 
The  organic  poisons  are  so  easily  acted  upon  by  the  fluids  of  the  system,  that  in 
one  case,  though  four  grains  were  taken,  and  death  ensued  very  quickly,  yet  the 
"  chromatic  test "  failed  to  detect  the  presence  of  strychnine  in  the  stomach. 
However,  the  murderer  is  not  to  escape.  This  is  the  only  poison  except  brucite 
(and  that  also  is  extracted  from  mix  vomica)  that  produces  tetanus  or  lock-jaw. 
This  symptom  proves  to  the  physician  that  death  has  been  caused  by  this  alka- 
loid. To  exhibit  the  effect  of  the  poison  a  frog  may  be  brought  into  the  court- 
room and  made  to  show  its  action.  So  sensitive  is  this  little  animal,  that  a  few 
drops  of  oil  containing  only  a  hundred-thousandth  of  a  grain  of  strychnine  will 
instantly  throw  it  into  a  rigid  locked-jaw,  in  which  it  is  incapable  of  the  least 
motion. 

*  Tea-raising.— Tea-plants  resemble  in  some  respects  the  low  whortleberry 
bush.  They  are  raised  in  rows,  three  to  five  in  a  hill,  very  much  as  corn  is  with 
us,  but  they  are  not  allowed  to  grow  over  one  and  a  half  feet  high.  The  medium- 
sized  leaves  are  picked  by  hand,  the  largest  ones  being  left  to  favor  the  growth 
of  the  bushes.  Each  little  hill  or  clump  will  furnish  from  three  to  five  ounces  of 
green  leaves,  or  about  one  ounce  of  tea,  in  the  course  of  the  season.  The  leaves 
are  first  wilted  in  the  sun,  then  trodden  in  baskets  by  barefooted  men  to  break 
the  stems,  next  rolled  by  the  hands  into  a  spiral  shape,  then  left  in  a  heap  to 
heat  again,  and  finally  dried  for  the  market.  This  constitutes  Black  Tea,  and 
the  color  would  be  produced  in  any  leaves  left  thus  to  wilt  and  heat  in  heaps  in 
the  open  air.  The  Chinese  always  drink  this  kind  of  tea.  They  use  no  milk  or 
sugar,  and  prepare  it,  not  by  steeping,  but  by  pouring  hot  water  on  the  tea  and 
allowing  it  to  stand  for  a  few  minutes.  Whenever  a  friend  calls  on  a  Chinaman, 
common  politeness  requires  that  a  cup  of  tea  be  immediately  offered  him. 

Ghven  Tea,  is  prepared  like  black,  except  that  it  is  not  allowed  to  wilt  or  heat, 
and  is  quickly  dried  over  a  fire.  It  is  also  very  frequently,  if  not  always,  col- 
ored—cheap black  teas  and  leaves  of  other  plants  being  added  in  large  quantities. 
In  this  country,  damaged  teas  and  the  "grounds"  left  at  hotels  are  re-rolled, 
highly  colored,  packed  in  old  tea-chests,  and  sent  out  as  new  teas.  Certain 
varieties  of  black  tea  even  receive  a  coating  of  black-lead  to  make  them  shiny. 

t  This  is  lost  in  the  "  grounds."  The  Japanese,  however,  eat  the  tea-leaves, 
and  so  save  this  nutritive  part. 


216  ORGANIC     CHEMISTRY. 


ORGANIC    COLORING    PRINCIPLES. 

THE  organic  coloring  principles  are  generally  of  vege- 
table origin.  They  are  found  in  the  roots,  wood,  bark, 
flowers,  and  seeds  of  plants. 

^Dyeing '. — Very  few  of  the  colors  have  such  an  affin- 
ity for  the  fibres  of  the  cloth  that  they  will  not  wash  out. 
Those  which,  like  indigo,  will  dye  directly,  are  called  sub- 
stantive colors.  But  the  majority  are  adjective  colors 
which  require  a  third  substance  having  an  attraction  for 
both  the  coloring  matter  and  the  cloth,  to  hold  them  to- 
gether. Such  substances  are  called  mordants  (mordeo,  to 
bite),  because  they  bind  the  dye  in  the  cloth,  thus  making 
a  "  fast  color."  The  most  common  mordants  are  alum, 
tin  oxide,  and  copperas.  In  dyeing,  the  cloth  is  first 
dipped  into  a  solution  of  the  mordant,  and  then  into  one 
of  the  dye-stuff.  The  mordant,  by  means  of  a  stamp, 
may  be  applied  to  the  cloth  in  the  form  of  a  pattern,  and 
when  it  is  afterward  washed,  the  color  will  be  removed 
except  where  the  mordant  fixed  it  in  the  printed  figure. 
The  same  dye  will  produce  different  colors  by  a  change 
of  mordants. — Example :  Madder  with  iron  gives  a  fine 
purple,  with  alum  a  pink,  and  with  iron  and  alum  a 
chocolate.  This  principle  lies  at  the  basis  of  dyeing 
"prints."* 

*  A  calico-printing  machine  is  very  complex.  The  cloth  passes  between  a 
series  of  rollers,  upon  which  the  corresponding  mordant  is  put,  as  ink  is  on  type. 
A  single  machine  sometimes  prints  from  twenty  sets  of  rollers ;  yet  each  im- 
pression follows  the  other  so  accurately,  that  when  the  cloth  has  passed  through, 
the  entire  pattern  is  printed  upon  it  with  the  different  mordants  more  perfectly 
than  any  painter  could  do  it,  and  so  rapidly  that  a  mile  of  cloth  has  been  printed 
with  four  mordants  in  an  hour.  The  cloth  when  it  leaves  the  printing  machine, 
though  stamped  with  the  mordants  in  the  form  of  the  figure,  betrays  nothing  of 


ORGANIC     COLORING     PRINCIPLES. 

Coloring  Substances.  — Madder  is  the  root  of  a  plant 
found  in  the  East,  and  extensively  cultivated  elsewhere. 
When  first  dug  it  is  yellow,  but  by  exposure  it  absorbs  0 
and  becomes  red.  It  is  used  in  dyeing  the  brilliant  Turkey- 
red.  The  coloring  principle,  which  is  named,  alizarine,  is 
said  to  be  identical  with  that  derived  from  anthracene,  a 
hydrocarbon  found  in  coal-tar  (see  p.  208).  Cochineal  is  a 
dried  insect  that  in  life  lives  upon  a  species  of  cactus 
in  Central  America.  The  coloring  matter  is  called  Oar- 
mine.  It  yields  the  brightest  crimson  and  purple  dyes.* 
Brazil-wood  furnishes  a  red  which  is  not  very  permanent. 
It  is  used  for  making  red  ink.  The  indigo  of  commerce 
is  obtained  from  a  bushy  plant  found  in  the  East 
Indies.  By  fermenting  for  some  days  in  vats  of  water, 
the  coloring  matter  is  developed.  Eeducing  agents 
change  indigo  into  a  soluble  and  colorless  substance  by 
the  absorption  of  H.f  It  is  then  called  "white  indigo." 
In  this  form  it  is  extensively  used  in  dyeing.  The  cloth 
becomes  permanently  colored  on  exposure  to  the  air,  when 
the  insoluble  blue  indigo  is  formed  in  its  fibres.  Logwood 
is  so  named  because  imported  in  logs.  It  is  the  heart 
of  a  South  and  Central  American  tree.  With  a  mordant 
of  alum  it  dyes  black.  Litmus  is  obtained  from  a 
variety  of  lichens  common  along  the  southern  coast  of 


the  real  design  until  after  being  dipped  in  the  dye,  which  acting  on  the  different 
mordants  brings  out  the  desired  colors.  The  print  is  now  washed,  glazed,  and 
fitted  for  the  market. 

*  The  purple  of  which  we  read  in  ancient  writings  was  a  secret  with  the 
Tyrians.  King  Huram,  we  learn,  sent  a  workman  to  Solomon  skilled  in  this 
art.  The  dye  was  obtained  from  a  shell-fish  that  was  found  on  the  coast  of 
Phoenicia.  Each  animal  yielded  a  tiny  drop  of  the  precious  liquid.  "  A  yard  of 
cloth  dipped  twice  in  this  costly  dye  was  worth  $150." 

t  Dissolve  a  little  indigo  in  strong  HaS04.  Color  a  test-tube  of  HaO  with  the 
solution.  Add  a  drop  of  HNO3,  and  on  gently  heating,  the  color  will  disap- 
pear. 

10 


218  ORGANIC    CHEMISTRY. 

Europe.  Its  juice  is  colorless,  but  on  the  addition  of 
H3N  it  assumes  a  rich  purple  blue.  Leaf -green  (chloro- 
phyll), as  found  in  plants,  is  a  resinous  substance  con* 
taining  several  coloring  matters.  It  seems  to  be  devel- 
oped by  the  action  of  the  sunbeam.  Plants  removed  from 
a  dark  cellar  to  the  sunlight  rapidly  turn  green. 


THE     OILS     AND     FATS. 

THE  oils  and  fats  are  derived  from  both  the  vegetable 
and  the  animal  kingdom.  They  are  divided  into  two 
classes— -fixed  and  volatile.  The  former  make  soaps,  the 
latter  do  not.  The  former,  when  heated  above  500°,  give 
off  acrid  and  offensive  vapors ;  *  the  latter  may  be  distilled 
without  alteration.! 

1.     THE      FIXED      OILS. 

Composition .  —  The  fatty  bodies  are  salts,  being 
composed  of  stearin,  palmitin,  and  olein.\  These  consist 
of  three  acids,  stearic,  palmitic,  and  oleic,  combined  with 
a  common  base — glycerin. 

The  first  two  of  these  salts  are  solids  at  common 
temperatures,  and  form  fats ;  the  last  is  a  liquid,  and 
forms  oils.  The  relative  proportion  of  olein  contained 

*  At  a  higher  temperature  they  are  decomposed,  and  among  the  products  is  an 
acrid  substance  (acroleiri)  with  which  we  are  familiar  in  the  disagreeable  smell 
of  a  smouldering  candle-wick  and  in  burning  fat. 

t  "  The  former  produce  a  permanent  stain  on  paper,  the  latter  do  not.  A  cork 
twisted  into  the  neck  of  a  bottle  containing  a  fixed  oil  makes  no  noise ;  in  a 
volatile  oil  it  squeaks." 

$  Stearin,  from  stear,  suet ;  palmitin,  since  it  is  abundant  in  palm  oil  •  olein, 
from  oleum,  oil ;  glycerin,  from  glukeros,  sweet. 


THE    FIXED     OILS.  219 

in  any  fatty  substance  determines  its  fluidity. — Example : 
Stearin  is  abundant  in  tallow,  and  palmitin  in  butter; 
hence  their  comparative  consistency.  Lard,  on  the  other 
hand,  contains .  so  much  olein  that  it  is  expressed  as 
"  lard-oil."  Olive-oil  contains  much  olein  and  palmitin ; 
the  former  remains  fluid  at  ordinary  temperatures,  but 
the  latter,  in  cold  weather,  hardens  into  a  thick  deposit, 
and  renders  the  oil  viscid. 

Glycerin  (C3H803)  is  an  odorless,  transparent  syrup. 
It  is  soluble  in  H20  and  alcohol.  On  account  of  its 
healing  properties  its  use  is  common  in  dressing  wounds, 
insect  bites,  chapped  hands,  etc. 

By  the  action  of  HN03  and  H2S04  glycerin  is  con- 
verted into  nitro-glycerin  [C3H5(N02)303],  an  oil  that 
explodes  with  fearful  violence  by  the  slightest  concussion, 
or  even  from  unexplainable  causes.  It  is  much  used  in 
blasting. 

Soap. — If  sweet-oil  and  H20  be  placed  in  a  test-tube 
and  shaken,  they  will  mix  but  not  unite ;  for  on  standing, 
the  oil  will  rise  to  the  top.  Add,  however,  caustic  potash 
or  a  little  "lye"  (see  p.  128),  when,  on  heating,  a  clear, 
soapy  solution  will  be  formed.  The  K  of  the  alkali  has 
combined  with  the  oleic  and  palmitic  acids  of  the  oil, 
making  two  new  salts — potassium  oleate  and  potassium 
palmitate ;  while  the  expelled  glycerin  remains  floating 
in  the  liquid. 

The  manufacture  of  soap  is  based  on  this  principle.  A 
variation  in  the  alkaline  base  and  the  fat  or  oil  used,  pro- 
duces the  different  kinds  of  soap.  Potash,  on  account  of 
its  affinity  for  H20,  forms  soft-soap.  Soda*  is  not  deli- 

*  A  deliquescent  substance  is  one  which  dissolves  in  HaO,  which  it  absorbs 
from  the  air. 


ORGANIC     CHEMISTRY. 

quescent,  and  hence  makes  hard-soap.*  Lard  forms  a 
softer  soap  than  tallow.  Castile  soap  is  made  from  olive 
oil  and  soda.  Its  mottled  appearance  is  due  to  the 
coloring  matter  which  is  stirred  through  it  while  it  is 
yet  soft.  Home-made  soap  is  prepared  by  boiling  "  lye  " 
and  "  grease."  f  As  the  latter  contains  such  a  variety 
of  fatty  substances  the  soap  generally  consists  of  the 
three  salts  —  potassium  oleate,  palmitate,  and  stearate. 
Yellow  soap  contains  some  resin  in  place  of  fat.  Cocoa- 
nut-oil  makes  a  soap  which  will  dissolve  in  salt  water, 
as  it  contains  an  excess  of  alkali.  Soap-balls  are  made 
by  dissolving  soap  in  a  very  little  water,  and  then  work- 
ing it  with  starch  to  a  proper  consistency  to  be  shaped 
into  balls.  White  toilet-soaps  are  made  from  lard  and 
soda.  The  curdling  of  soap  in  hard  water  is  caused  by 
the  formation  of  a  calcium  or  a  magnesium  soap  which 
is  insoluble  in  H20,  and  floats  on  the  top  as  a  greasy 


The  Cleansing  Qualities  of  Soap  .  —  There  ex- 
udes constantly  from  the  pores  of  the  skin  an  oily  per- 
spiration, and  this  catching  the  floating  dust  dries  into  a 
film  which  will  not  dissolve  in  H20.  The  alkali  of  the 
soap  combines  with  this  oily  substance  and  makes  a  solu- 
ble soap.  In  addition,  the  alkali  also  dissolves  the  cuticle 
of  the  skin,  and  thus  produces  the  "  soapy  feeling,"  as  we 
term  it,  when  we  handle  soap. 

*  Soap  is  frequently  adulterated  with  gypsum,  lime,  pipe-clay,  or  sodium 
silicate.  These  may  be  detected  by  dissolving  a  piece  of  the  soap  in  water  or 
alcohol,  and  noticing  if  there  be  any  precipitate. 

t  The  heat  hastens  the  chemical  change,  which  takes  place  more  slowly  in 
making  what  is  known  as  "  cold  soap." 

J  A  soap  made  from  lard,  in  water  containing  calcium  carbonate,  wduld  un- 
dergo the  following  reaction  :  Potassium  oleate  +  calcium  carbonate  =  calcium 
oleate  +  potassium  carbonate. 


THE     FIXED      OILS.  2%1 

Saponification  (sapo,  soap ;  facere,  to  make)  is  the 
process  of  separating  the  fatty  acids  and  glycerin,  and  is 
so  named  even  when  no  soap  is  formed.  One  method  is 
as  follows :  Tallow  or  lard  is  boiled  with  lime,  and  thus 
made  into  a  calcium  soap.  This  is  decomposed  by  H2S04, 
forming  calcium  sulphate,  which,  being  insoluble,  sinks 
to  the  bottom,  leaving  the  three  acids  of  the  fat  floating 
upon  the  surface.*  The  glycerin  is  also  left  by  itself  in 
the  liquid,  from  whence  it  is  removed  and  prepared  for 
the  market.  The  acids,  when  cool,  are  subjected  to  great 
pressure ;  the  oleic  flows  out,  leaving  the  stearic  and  pal- 
mitic acids  as  a  milk-white,  odorless,  tasteless  solid,  which 
is  commonly  called  stearin,  and  extensively  used  in  the 
manufacture  of  stearin  or  adamantine  candles.\ 

Wax  is  found  in  nearly  all  plants.  It  forms  the  shiny 
coating  of  the  leaves  and  fruit. — Example :  Lemon  leaf, 
apple.  Certain  plants  in  Japan  contain  so  much  wax 
that  it  is  separated  by  boiling  and  used  for  making  can- 
dles. Bees,  even  when  fed  on  sugar  alone,  have  the 
power  of  converting  it  into  wax,  which  is  therefore  to  be 
regarded  as  an  animal  secretion. — MILLEE.  Beeswax  is 
bleached  by  exposure  to  the  air  in  thin  ribbons. 
Z/inseed  Oil  is  a  drying  oil,  as  it  is  termed — i.  e.,  it 

*  Fat  is  also  decomposed  by  the  action  of  superheated  steam,  which  at  once 
liberates  the  fatty  acids. 

t  Paraffine  candles  are  made  from  coal-oil.  Wax  candles  are  manufactured  by 
the  following  process :  A  large  number  of  cotton  wicks  are  hung  upon  a  revolv- 
ing frame  with  projecting  arms.  The  wicks  are  fitted  at  the  ends  with  metal 
tags  to  keep  the  wax  from  covering  that  part.  As  the  machine  slowly  turns,  a 
man,  standing  ready  with  a  vessel  of  melted  wax,  carefully  pours  a  little  upon 
each  wick  in  succession.  This  process  is  repeated  until  the  candles  reach  the 
desired  size.  They  are  then  rolled  on  a  smooth  stone  slab,  the  tops  cut  by 
conical  tubes,  and  the  bottoms  trimmed,  when  they  are  ready  for  use.  The  large 
tapers  burned  in  Catholic  cathedrals  are  made  by  placing  the  wick  on  a  sheet  of 
wax,  rolling  it  up  till  the  right  thickness  is  reached,  when  the  candle  is  trimmed 
and  polished  as  before.  Spermaceti  candles  are  run  from  the  white,  crystalline, 
solid  fat  which  is  found  with  sperm  oil  in  the  head  of  the  sperm  whale. 


ORGANIC     CHEMISTRY. 

absorbs  0  from  the  air,*  and  hardens  by  exposure.  It  ia 
expressed  from  flaxseed,  which  furnishes  about  one-fifth 
of  its  weight  in  oil.  Boiled  oil  is  made  by  heating  the 
crude  oil  with  litharge,  which  entirely  dissolves  and 
greatly  increases  the  drying  property  of  the  oil.  Linseed 
oil  is  used  in  mixing  paints  and  varnishes.  Putty  con- 
sists of  linseed  oil  and  whiting  well  mixed.  Printers'  ink 
is  made  by  heating  linseed  oil  until  it  becomes  thick  and 
viscid,  when  lampblack  is  added  to  give  it  the  proper 
consistency. 

Cod-2irer  Oil  is  extracted  from  the  liver  of  the  cod- 
fish. It  contains  I,  Br,  and  P,  and  is  much  used  as  a 
remedy  in  consumption. 

Croton  Oi2  is  made  from  the  seeds  of  an  Indian 
plant ;  it  is  a  powerful  medicinal  agent. 

Cctslor  Oil  is  extracted  from  the  castor-oil  bean.  It 
is  used  in  medicine,  and  also  in  perfumery  and  hair-oils. 

Sweet  or  O2ive  Oil  is  expressed  from  the  olive  fruit. 
It  is  an  unctuous  oil,  i.  e.,  it  absorbs  0  on  exposure  to  the 
air — not  hardening  like  the  drying  oils,  but  remaining 
sticky,  and  after  a  time  becoming  rancid.f  In  the  south- 
ern part  of  Europe,  olive-oil  is  extensively  used  as  an 
article  of  food. 

2.     THE    VOLATILE     OILS. 
THE  volatile  oils,  unlike  the  fixed,  make  no  soaps,  and 

*  This  absorption  of  O  is  sometimes  so  rapid  as  to  be  attended  by  sufficient 
heat  as  to  cause  the  mass  to  take  fire ;  and  several  serious  conflagrations  have 
been  traced  to  such  spontaneous  combustion.  (See  p.  93.) 

t  This  change  is  attended  by  a  slight  absorption  of  O,  and  appears  to  be  due 
to  the  decomposition  of  certain  mucilaginous  and  albuminous  matters,  which, 
during  their  decay,  react  on  the  fat,  setting  free  the  fatty  acids,  and  decomposing 
the  glycerin.  Perfectly  pure  fats  and  oils  do  not  become  rancid.— MILLER. 


THE     VOLATILE     OILS. 

dissolve  readily  in  alcohol  or  ether.  Their  solution  in 
alcohol  forms  an  essence. 

Sources. — The  volatile  or  essential  oils  are  of  vegetable 
origin.  They  are  found  in  the  petals  of  a  flower,  as  the 
violet;  in  the  seed,  as  caraway;  in  the  leaves,  as  mint, 
or  in  the  root,  as  sassafras.  Sometimes  several  kinds  of 
oil  are  obtained  from  different  parts  of  the  same  plant. — 
Example :  In  the  orange  tree,  the  flower,  leaves,  and  rind 
of  the  fruit  furnish ,  each  its  own  variety.  The  perfume 
of  flowers  is  produced  by  these  volatile  oils;  but  how 
slight  a  quantity  is  present  may  be  inferred  from  the 
statement  that  "  one  hundred  pounds  of  fresh  roses  will 
give  scarcely  a  quarter  of  an  ounce  of  Attar  of  Koses." 

Preparation. — In  the  peppermint,  the  wintergreen,  and 
many  others,  the  plant  is  distilled  with  water.  The  oils 
pass  over  with  the  steam,  and  are  condensed  in  a  refrig- 
erator connected  with  the  "  Mint  Still."  The  oil  floats 
on  the  surface  of  the  condensed  water,  and  may  be 
removed.  A  small  portion,  however,  remains  mingled 
with  the  latter,  which  thus  acquires  its  peculiar  taste  and 
odor,  constituting  what  is  termed  a  "  perfumed  water." 
In  some  flowers,  as  the  violet,  jasmine,  etc.,  the  perfume 
is  too  delicate  to  be  collected  in  this  manner.  They  are 
therefore  laid  between  woollen  cloths  saturated  with 
some  fixed  oil.  This  absorbs  the  essential  oil,  which  is 
then  dissolved  by  alcohol.  The  oil  of  lemon  or  orange  is 
obtained  from  the  rind  of  the  fruit  by  expression  or  by 
digesting  in  alcohol. 

Composition. — C,0H|6  is  the  common  symbol  of  a  large 
number  of  these  oils.  Thus  the  oils  of  lemon,  cloves, 
juniper,  birch,  black  pepper,  ginger,  bergamot,  turpen- 
tine, cubebs,  oranges,  etc.,  nearly  twenty  in  all,  are  iso- 


ORGANIC     CHEMISTRY. 

meric.  They  are  pure  hydrocarbons.  A  second  class 
contains  0,  and  a  third  S. 

Jffirst  Class  of  Volatile  Oils.  —  The  oil  of  tur- 
pentine (Ci0H|6)  is  a  type  of  this  division.  It  is  made  by 
distilling  pitch  with  H20.  It  is  generally  called  spirits 
of  turpentine.  It  is  highly  inflammable,  and,  owing  to 
the  excess  of  C,  burns  with  a  great  smoke.  By  the  union 
of  two  atoms  of  its  H  with  an  atom  of  the  0  of  the  air  to 
form  H20,  it  is  converted  into  rosin.*  Oamphene  is  tur- 
pentine purified  by  repeated  distillation.  Burning-fluid 
is  a  mixture  of  camphene  and  alcohol.  In  the  heat  of 
the  burning  H  of  the  latter,  the  C  of  the  former  is  con- 
sumed, and  this  produces  a  bright  light.  The  tendency 
of  camphene  to  smoke  is  thus  diminished,  and  the  illu- 
minating power  increased.  By  the  action  of  H  Cl  on  tur- 
pentine or  oil  of  lemons  an  artificial  camphor  is  produced 
which  much  resembles  common  camphor. 

The  Second  Class  includes  camphor,  the  oils  of 
bitter  almonds,  cinnamon,  spearmint,  wintergreen,  etc. 
Camphor  (C|0HI60)  is  obtained  by  distilling  the  roots  and 
leaves  of  the  camphor-tree  with  water,  and  condensing 
the  vapors  on  rice-straw.  It  is  purified  by  sublimation. 
When  kept  in  a  bottle,  it  vaporizes,  and  its  delicate  crys- 
tals collect  on  the  side  toward  the  light.  Taken  inter- 
nally, except  in  small  doses,  it  is  a  virulent  poison.  Its 
solution  in  alcohol  is  called  "  spirits  of  camphor."  If  H20 
be  added  to  this,  the  camphor  will  be  precipitated  as  a 
flour-like  powder,  f 

*  In  this  way,  the  turpentine  around  the  nozzle  of  a  bottle  in  which  it  is 
kept  becomes  first  sticky  and  then  resinous.  Old  oil  should  not  be  taken  to 
remove  grease  spots,  as,  while  it  will  remove  one,  it  will  leave  another  of  its 
own. 

t  Though  camphor  gum  is  powdered  with  difficulty,  a  few  drops  of  alcohol  will 


RESINS     AND     BALSAMS. 

The  ffiird  C2ass  includes  garlic,  assafoetida,  onions, 
mustard,  horse-radish,*  etc.  They  are  known  for  their 
pungent  taste  and  the  disagreeable  odor  they  often  in> 
part  to  the  breath.  \ 


THE    RESINS    AND    BALSAMS. 

THE  resins  are  generally  formed  from  the  essential  oils 
by  oxidation. — MILLER. — Example:  Turpentine,  as  we 
have  just  seen,  is  changed  to  rosin,  a  resinous  substance. 
If  the  resin  is  dissolved  in  some  essential  oil,  it  is  called  a 
balsam. — Example  :  Pitch  is  a  true  balsam,  since  by  dis- 
tillation it  is  separated  into  rosin  and  turpentine.  They 
generally  exude  from  incisions  in  trees  and  shrubs,  in  the 
form  of  a  balsam,  which  oxidizes  on  exposure  to  the  air, 
and  becomes  a  resin.  —  Example:  Spruce  gum.  The 
resins  are  translucent  or  transparent,  brittle,  insoluble  in 
H20,  but  soluble  in  ether,  alcohol,  or  any  volatile  oil,  and 
form  varnishes.  They  are  non-conductors  of  electricity, 
and  burn  with  much  smoke.  They  do  not  decay,  and, 
indeed,  have  the  power  of  preserving  other  substances.  J 

ffiosin  constitutes  about  75  per  cent,  of  pitch,  a  resin- 
ous substance  which  exudes  from  incisions  made  in  the 

remove  all  trouble.  When  small  particles  of  powdered  camphor  are  thrown  on 
water  free  from  grease,  each  fragment  begins  to  dissolve  with  a  remarkable  gyra- 
tory motion,  which  is  instantly  checked  by  a  drop  of  an  essential  oil  allowed  to 
fall  upon  the  surface  of  the  liquid. 

*  The  essential  oil  of  garlic,  onions,  etc.,  is  the  sulphide  of  allyl,  a  radical  hav- 
ing the  formula  C3H5 ;  the  oil  of  horse-radish  is  the  sulpho-cyanide  of  allyl. 

t  The  oil  of  mustard  is  not  contained  in  the  seed,  but  is  formed  in  it  by  the 
action  of  water  and  a  latent  ferment.  This  is  the  reason  why  mustard,  when 
first  prepared  for  the  table,  is  bitter,  but  becomes  pungent  after  a  little  time. 

$  For  this  reason  they  were  used  in  embalming  the  bodies  of  the  ancient 
Egyptians,  which,  after  the  lapse  of  two  thousand  years,  are  yet  found  dried  into 
mummies  in  their  mammoth  tombs— the  Pyramids. 


226  ORGA  NIC     CHE  MIS  TR  Y. 

trunks  of  certain  species  of  pine.  It  is  used  in  making 
soaps,  to  increase  friction  in  violin-bows  and  the  cords 
of  clock-weights,'  and  in  soldering. 

Z,ac  exudes  from  the  ficus-tree  of  the  East  Indies. 
An  insect  punctures  the  bark,  and  the  juice  flows  out 
over  the  insect,  which  works  it  into  cells  in  which  to 
deposit  its  eggs.  The  dried  gum  incrusting  the  twigs  is 
called  stick-lac ;  when  removed  from  the  wood,  seed-lac ; 
when  melted  and  strained,  shellac.  The  liquefied  resin 
is  dropped  upon  large  leaves,  and  so  cools  in  broad,  thin 
pieces.  Sealing-wax  is  made  of  shellac  and  Venice  tur- 
pentine; vermilion  being  added  to  give  the  red  color. 
Shellac  is  much  used  in  making  varnishes. 

Gum  ^Benzoin  also  exudes  from  a  tree  in  the  East 
Indies.  It  is  the  principal  source  of  benzoic  acid.  It  is 
used  in  fumigation  and  in  cosmetics,  and  on  account  of 
its  fragrant  odor  is  burnt  as  incense.* 

Amber  is  a  fossil  resin  which  has  exuded  in  some 
past  age  of  the  world's  history  from  trees  now  extinct. 
It  is  sometimes  found  containing  various  insects  perfectly 
preserved,  which  were  without  doubt  entangled  in  the 
mass  while  it  was  yet  soft.  These  are  so  beautifully 
embalmed  in  this  transparent  glass  that  they  give  us  a 
good  idea  of  the  insect  life  of  that  age.  Amber  is  cast 
up  by  the  sea,  principally  along  the  shores  of  the  Baltic ; 
although  it  is  also  found  in  beds  of  lignite.  It  is  com- 
monly translucent,  and  susceptible  of  a  high  polish.  It 
is  used  for  ornaments,  mouth-pieces,  necklaces,  buttons, 
etc. ;  and  is  an  ingredient  of  carriage  varnish. 

*  Place  some  green  sprigs  under  a  glass  receiver,  and  at  the  bottom  a  hot  iron, 
on  which  sprinkle  a  little  benzoic  acid.  It  will  sublime  and  collect  in  beautifully 
delicate  crystals  on  the  green  leaves  above,  making  a  perfect  illustration  of  win- 
ter frost-work. 


RESINS    AND    BALSAMS. 

Caoulcfiotic  or  India-rubber  (zC5H8)  is  a  mix- 
ture of  several  hydrocarbons.  It  exudes  from  certain 
trees  in  South  America  as  a  milky  juice.*  The  solvents 
of  rubber  are  ether,  naphtha,  turpentine,  chloroform,  bi- 
sulphide of  carbon,  etc.  It  melts,  but  does  not  become 
solid  on  cooling.  Freshly-cut  surfaces  readily  cohere : 
this  property,  together  with  its  power  of  resisting  most 
reagents,  renders  it  invaluable  to  the  chemist  in  making 
flexible  joints  and  tubes.  "  It  loses  its  elastic  power  when 
stretched  for  a  long  time,  but  recovers  it  on  being  heated. 
In  the  manufacture  of  rubber  goods  for  suspenders,  etc., 
the  rubber  thread  is  drawn  over  bobbins  and  left  for  some 
days  until  it  becomes  inelastic.  In  this  state  it  is  woven, 
after  which  a  hot  wheel  is  rolled  over  the  cloth  to  restore 
the  elasticity."  f 

Yuicanized  ffiiibber  is  made  by  heating  caoutchouc 
with  a  small  amount  of  sulphur.  This  constituted  Good- 
year's  original  patent. f  It  is  less  liable  to  be  hardened 

*  The  globules  of  rubber  are  suspended  in  it  as  butter  is  in  milk.  By  adding 
H3N  the  sap  may  be  kept  unchanged  for  months,  and  is  sometimes  exported  in 
that  form  preserved  in  tightly  corked  bottles.  The  tree,  it  is  said,  yields  about 
a  gill  per  day  from  each  incision  made.  A  little  clay  cup  is  placed  underneath, 
from  which  the  juice  is  collected  and  poured  over  clay  or  wooden  patterns  in 
successive  layers  as  it  dries.  To  hasten  the  process  it  is  carried  on  over  large 
open  fires,  the  smoke  of  which  gives  to  the  rubber  its  black  color ;  when  pure  it 
is  almost  white.  When  nearly  hard,  the  rubber  will  receive  any  fanciful  design 
which  may  be  marked  upon  it  with  a  pointed  stick.  The  natives  often  form  the 
clay  into  odd  shapes,  as  bottles,  images,  etc.,  and  the  rubber  is  sometimes  ex- 
ported in  these  uncouth  forms. 

t  Mr.  Goodyear  had  been  experimenting  to  find  some  way  of  rendering  rubber 
insensible  to  heat  and  cold.  It  is  said  that  one  day,  while  talking  with  a  friend, 
he  happened  to  drop  a  bit  of  S  in  a  pot  of  melted  rubber.  By  one  of  those  happy 
intuitions  which  seem  to  come  only  to  men  of  genius,  he  watched  the  process, 
and  to  his  amazement  found  that  while  the  appearance  of  the  rubber  was  the 
same — elastic,  odorous,  and  tasteless — its  stickiness  was  gone,  and  it  had  gained 
the  properties  he  so  much  desired.  He  immediately  took  out  a  patent  in  this 
country  and  sailed  for  England,  where,  instead  of  securing  his  secret  by  a  simi- 
lar patent,  he  offered  to  sell  it  for  £10,000.  Charles  Hancock,  with  whom  he  had 
been  corresponding  for  several  years,  and  who  had  been  engaged  in  similar 
experimenting,  resolved  to  discover  it  himself.  He  shut  himself  up  in  his  labo« 


ORGANIC     CHEMISTRY. 

by  cold  or  softened  by  heat,  and  admits  of  many  uses  to 
which  common  rubber  would  be  entirely  unsuited.  If 
sulphurized  rubber  be  heated  to  a  high  temperature  it 
becomes  a  hard,  brittle,  black  solid,  capable  of  a  high 
polish,  which  is  used  for  knife-handles,  combs,  buttons, 
etc. 

G-utta-percha  (C2oH32)  resembles  caoutchouc  in  its 
source,  preparation,  and  appearance.  It  softens  in  warm 
water,  and  can  then  be  moulded  like  wax.  When  cooled 
it  assumes  its  original  solidity.  It  is  extensively  used 
in  taking  impressions  of  medals,  etc. 


THE    ALBUMINOUS    BODIES. 

•     . 

THESE  are  albumen,  casein,  gelatin,  and  fibrin.  Owing 
to  the  complexity  of  their  composition,  no  satisfactory 
formula  can  be  assigned  to  them.  The  molecule  of  albu- 
men has  been  stated  as  C72H,,0N,8S022>  tort  it  is  very 
uncertain.* 

Mbumen  is  found  nearly  pure  in  the  whites  of  eggs  f 
— hence  the  name  (albus,  white).  It  exists  in  two  amor- 
phous conditions — as  a  liquid  in  the  sap  of  plants,  the 
humors  of  the  eye,  serum  of  the  blood,  etc. ;  and  as  a 

ratory  and  went  to  work.  Disheartening  failures  marked  every  attempt.  At 
last  he  tried  S.  At  first,  he  did  not  succeed ;  but,  persevering,  he  finally  saw, 
amid  the  stifling  fumes  of  brimstone,  the  soft  rubber  metamorphosed  into  the 
vulcanized  caoutchouc.  He,  too,  was  possessed  of  the  secret,  and,  taking  out  a 
patent,  reaped  the  reward  of  his  patient  labor. 

*  Many  chemists  regard  albumen,  casein,  fibrin,  etc.,  as  chemically  identical 
and  capable  of  being  converted  by  the  vital  force  one  into  the  other.  These 
bodies  are  sometimes  called  Protein  (protos,  first)  on  the  supposition  that  they 
were  derived  from  a  single  azotized  principle  named  protein. 

t  Strange  to  say,  "  the  venom  of  the  rattlesnake  is  isomeric  with  the  '  whites 
Of  eggs.'" 


THE    ALBUMINOUS    BODIES.  229 

solid  in  the  seeds  of  plants,  and  the  nerves  and  brains  of 
animals.* 

Properties. — It  is  soluble  in  cold,  but  insoluble  in  hot 
H20.  At  a  temperature  of  about  140°  F.  it  coagulates. 
This  change  we  always  see  in  the  cooking  of  eggs ;  yet 
nothing  is  known  of  its  cause.  Alcohol,  corrosive  subli- 
mate, acids,  creosote,  and  solutions  of  copper,  lead,  silver, 
etc.,  have  the  power  to  coagulate  albumen.  In  cases  of 
poisoning  by  these  substances,  the  white  of  eggs  is  there- 
fore a  valuable  antidote,  as  it  wraps  them  in  an  insoluble 
covering,  and  so  protects  the  stomach. 

Casein  (caseus,  cheese)  is  found  in  the  curd  of  milk. 
In  the  presence  of  an  acid  it  coagulates,  and  thus  milk 
curdles  after  it  sours.  Rennet  (the  dried  stomach  of  a 
calf)  is  used  to  coagulate  milk  in  the  process  of  cheese- 
making,  but  the  cause  of  its  action  is  not  understood. 

Mi2fo  is  a  natural  emulsion,  composed  of  exceedingly 
minute  globules  diffused  through  a  transparent  liquid. 
The  globules  consist  of  a  thin  envelope  of  casein  filled 
with  butter.  .Being  a  trifle  lighter  than  H20,  they  rise 
to  the  surface  as  cream.  Churning  breaks  these  cover- 
ings, and  gathers  the  butter  into  a 
mass.  Milk  contains  some  sugar, 
which  by  a  peculiar  change  termed 
"  lactic  fermentation  "  is  converted 
into  lactic  acid.  The  casein  seems  to 
act  as  a  ferment  in  hastening  this 
oxidation,  and  by  its  decay  produces 
the  offensive  odor.  In  the  "  sour-  MUK  under  the  Microscope. 


*  This  principle  is  of  very  great  importance,  as  albumen  may  thus  be  carried 
by  the  blood  through  the  system,  but  when  once  deposited  it  cannot  be  dissolved 
and  washed  away  again. 


ORGANIC     CHEMISTRY. 

ing  "  of  milk  there  is  no  extrication  of  gas  and  no  absorp- 
tion of  0.  The  milk-sugar  (C|2H240|2)  disappears  and 
lactic  acid  (C3H603)  gradually  takes  its  place.  It  is  an 
excellent  illustration  of  a  complex  molecule  breaking  up 
into  simple  ones. — MILLER. 

Ge2atin .  —  Hot  water  dissolves  a  substance  from  ani- 
mal membranes,  skin,  tendons,  and  bones,*  which,  on 
cooling,  forms  a  yielding,  tremulous  mass  called  gelatin. 
In  calves-foot  jelly,  soups,  etc.,  it  is  well  known. f  Glue 
is  a  gelatin  made  from  bones,  hoofs,  horns,  etc.,  by  boil- 
ing in  H20  and  then  evaporating  the  solution.  Isinglass 
is«a  very  pure  gelatin,  obtained  from  the  air-bladders  of 
the  cod,  sturgeon,  and  other  fish.  Size  is  a  gelatin  pre- 
pared from  the  parings  of  parchment.  It  is  used  for 
sizing  paper  in  order  to  fill  up  the  pores  and  prevent  the 
ink  from  spreading,  as  it  does  on  unsized  or  blotting- 
paper. 

Fibrin  constitutes  chiefly  the  fibrous  portion  of  the. 

*  Bones  consist  of  organic  and  mineral  matter  combined. 
ANALYSIS.    (BerzeHus.) 

Gelatin 32.17 

Blood-vessels 1.13 

Phosphate  of  lime 51.04 

Carbonate  of  lime 11.30 

Fluoride  of  calcium 2.00 

Phosphate  of  magnesia 1.16 

Chloride  of  sodium  . .  .     1.20 


100.00 

By  soaking  a  bone  in  HC1  the  mineral  matter  will  all  be  dissolved,  and  the 
organic  matter  left  in  the  original  shape  of  the  bone,  but  soft  and  pliable.  If, 
Instead,  the  bone  be  burned  in  the  fire,  the  organic  matter  will  be  removed  and 
the  mineral  left  white  and  porous.  (See  Physiology,  p.  20.) 

t  As  an  article  of  food  it  is  of  very  little  nutritive  value.  It  may  answer  to 
dilute  a  stronger  diet,  but  of  itself  does  little  to  build  up  the  body  of  an  invalid. 
Beef-tea,  even,  is  now  thought  to  have  little  nourishing  property,  its  principal 
office  being  to  act  as  a  stimulant. 


THE     ALBUMINOUS     BODIES.  281 

muscles.    If  a  piece  of  lean  &Q-  u- 

beef  be  washed  in  clean  H20 
until  all  the  red  color  disap- 
pears, the  mass  of  white  tis- 
sue which  will  remain  is 
called  fibrin.  Like  albumen, 
it  exists  in  two  forms — as  a 
liquid  in  the  blood,  and  as  a 

FtJbnn,  or  Muscle. 

solid  in  the  flesh.    The  clot- 
ting of  blood  is  due  to  the  coagulation  of  the  fibrin. 
(See  Physiology,  p.  108.) 

•  Vegetable  Albumi?ioids . — Vegetables  contain  sub- 
stances which  are  scarcely  to  be  distinguished  from  the 
albuminous  bodies  derived  from  animal  sources.  If  wheat 
flour  be  made  into  a  dough,  and  then  kneaded  in  water 
until  the  soluble  portion  is  washed  away,  the  tough, 
sticky  mass  which  will  remain  is  called  gluten.  It  is  a 
nitrogenous  substance,  allied  to  albumen.  It  exists  most 
abundantly  in  the  bran  of  cereal  grains. 

By  treating  peas  as  we  do  potatoes  in  forming  starch, 
.and  then  adding  a  little  acid  to  the  water  which  is  left 
after  the  starch  settles,  an  albuminous  substance  is  depos- 
ited, which  is  thought  to  be  identical  with  casein.  The 
Chinese  use  it  largely  for  cheese.  It  is  found  abundantly 
in  the  seeds  of  peas,  beans,  etc.,  and  is  termed  legumin. 

'Putrefaction .  —  Owing  to  the  complex  structure  of 
albuminous  substances,  and  the  presence  of  N,  they  read- 
ily oxidize  and  form  new  and  simple  compounds.  This 
breaking  up  of  the  organic  structure  is  called  putrefac- 
tion. Any  albuminous  substance  thus  putrefying  may 
act  as  a  ferment.  This  probably  explains  the  danger 
physicians  incur  in  dissecting  a  dead  body.  The  least 


282  ORGANIC     CHEMISTRY. 

portion  of  the  decomposing  matter  entering  the  flesh, 
through  a  scratch  even,  is  liable  to  be  fatal.  The  absence 
of  H20  retards  chemical  change,  and  therefore,  meats, 
apples,  etc.,  are  preserved  by  drying.*  Salt  acts  somewhat 
in  the  same  way  by  absorbing  the  juice  of  the  meat,  and, 
while  it  covers  it  as  brine,  wards  off  the  attacking  0  ;  but 
as  it  dissolves  some  of  the  salts  and  other  valuable  ele- 
ments, it  makes  the  meat  less  nutritious. 


DOMESTIC    CHEMISTRY. 

Itf  the  chemistry  of  housekeeping  there  are  some 
points  not  yet  mentioned,  which  may  now  be  profitably 
discussed. 

JlfaMng  2tread.  —  Flour  consists  of  gluten,  starch, 
and  a  little  dextrine  and  sugar. 

The  oily  matter  and  the  salts — of  which  there  are  from 
one  to  twq  per  cent,  in  wheat — are  contained  mainly  in 
the  bran.  The  process  of  mixing  the  "  sponge  "  is  purely 
mechanical.  When  the  sponge  is  set  in  a  warm  place  to 
rise  (as  heat  favors  chemical  change),  the  yeast,  yeast- 
cake,  or  emptyings,!  as  the  case  may  be,  induces  a  rapid 

*  The  cold  also  protects  from  chemical  change.  The  bodies  of  mammoths 
have  been  found  in  the  frozen  soil  of  the  Arctic  regions  so  perfectly  preserved 
that  the  dogs  ate  the  flesh.  How  long  the  animals  had  been  there  we  cannot  tell, 
but  certainly  for  ages.  In  1861  the  mangled  remains  of  three  guides  were  found 
at  the  foot  of  the  Glacier  de  Boisson,  in  Switzerland.  They  had  been  lost  in  an 
avalanche  on  the  plateau  of  Mont  Blanc,  forty-one  years  before. 

t  Milk-emptyings  are  sometimes  used  in  making  bread.  In  this  case,  the 
mixture  of  flour  and  milk,  kept  at  a  temperature  of  about  "  blood  heat,"  rapidly 
develops  yeast,  which  produces  fermentation.  If  the  heat  is  much  above  this, 
the  plant  will  be  killed,  and  the  milk  be  merely  turned  to  lactic  acid.  Often- 
times, too,  the  side  of  the  dish,  near  the  fire,  may  be  warm  enough  to  produce 
yeast  and  to  generate  CO2  and  alcohol,  while  on  the  opposite  side  lactic  acid 
is  being  formed.  A  uniform  temperature  is  necessary,  and  this  can  best  be  ob- 


DOMESTIC     CHEMISTRY.  233 

fermentation,  converting  the  sugar  into  alcohol  and  C02. 
This  gas  is  diffused  through  the  mass,  and  being  retained 
by  the  tenacious  and  viscid  dough,  causes  it  to  "  rise,"  i.  e., 
to  swell  and  become  porous.  The  next  step  includes  the 
addition  of  fresh  flour,  and  a  laborious  process  of  "  knead- 
ing." The  latter,  so  essential  to  good  bread,  diffuses  the 
half -fermented  sponge  uniformly  through  the  dough ;  it 
also  breaks  up  into  smaller  ones  the  bubbles  of  gas  entan- 
gled in  the  gluten,  and  thereby  makes  the  bread  fine- 
grained. The  dough  is  now  "  moulded  "  into  loaves,  and 
then  placed  in  the  oven.  The  heat  rapidly  expands  the 
CO  2,  and  increases  the  porosity  of  the  bread.  The  starch 
granules  are  broken  up  and  the  alcohol  vaporized,  and, 
with  a  part  of  the  H20,  driven  off.  The  surface  gradually 
becomes  dry  and  hard,  and  losing  a  part  of  its  chemically 
combined  water,  is  partially  converted  into  a  substance 
allied  to  caramel,  thus  forming  the  crust.*  If  the  tem- 
perature of  the  oven  is  right,  the  cells  of  the  bread  will 
have  sufficient  strength  to  retain  their  form  after  the  gas 
and  vapors  have  escaped.  If  the  heat  is  not  sufficient,  or 
if  there  is  too  much  water  in  the  dough,  the  C02  escapes, 
the  cells,  not  being  sufficiently  hardened,  collapse,  and 
the  bread  is  "  slack-baked."  If  the  oven  is  too  hot,  the 
crust  forms  too  quickly  over  the  surface  of  the  loaf,  pre- 
venting the  escape  of  the  C02,  which  accumulates  at  the 
centre,  making  the  bread  hollow. 

Stale  IBread. — New  bread  consists  of  nearly  one- 
half  water.    In  stale  bread  this  disappears.    It  has,  how- 

tained  by  placing  the  dish  of  emptyings  in  a  kettle  of  warm  water  on  the  stove 
hearth. 

*  A  shiny  coat  is  given  to  the  loaf  ("  rusk")  by  moistening  the  crust  after  the 
bread  is  baked,  thus  dissolving  some  of  the  dextrine,  which  is  also  contained  in 
the  crust.  This  quickly  dries  oh  returning  it  to  the  oven. 


234  ORGANIC     CHEMISTRY. 

ever,  only  chemically  combined  with  the  solid  portions, 
and  may  be  brought  to  view  by  heating  the  loaf  in  a  close 
tin  vessel. 

JLerated  32read  is  made  in  the  following  manner : 
Flour  and  salt  are  put  in  a  revolving  copper  globe,  into 
which  H20  charged  with  C02  is  admitted.  When  well 
mixed,  a  stop-cock  is  turned  and  the  dough  is  driven  out, 
by  the  elastic  force  of  the  gas,  into  pans  ready  for 
baking. 

Sour  3?read  results  from  a  neglect  to  arrest  the  first 
stage  of  the  fermentation,  thus  allowing  the  second  stage 
to  commence  and  acetic  acid  to  be  formed.  The  acid  is 
neutralized  by  an  alkali,  as  saleratus,  or  soda. 

Griddle-calces  are  raised  by  the  addition  of  some 
ferment,  as  yeast ;  but  the  second,  or  acetic  stage,  is 
always  reached.  The  "  batter "  then  tastes  sour,  and  is 
sweetened  by  saleratus  or  soda.  The  acetic  acid  combines 
with  the  metallic  base,  forming  a  harmless  salt  which 
remains,  while  the  C02  bubbles  up  through  the  batter, 
making  it  "light." 

jRaising  ^Biscuit. — In  raising  biscuit,  or  cake,  soda 
and  cream  of  tartar  *  are  most  commonly  used.  The 
CO  2  is  set  free,  and,  escaping  as  a  gas,  makes  the  dough 
porous,  while  the  sodium  and  potassium  tartrate  (Eochelle 
salt)  which  is  left  is  a  simple  salt.  Ordinary  "  baking- 
powders  "  are  merely  cream  of  tartar  and  soda.  A  variety 
invented  by  Prof.  Horsford  contains  acid  calcium  phos- 
phate (see  note,  p.  140) ;  this  reacting  upon  the  "soda" 
forms  calcium  and  sodium  phosphates,  both  of  which  are 


*  Cream  of  tartar  is  often  adulterated  with  plaster,  lime,  chalk,  or  flour.  By 
dissolving  in  water,  these  impurities  can  be  detected,  as  they  form  an  insoluble 
precipitate ;  but  in  milk  as  commonly  used  in  cooking,  they  are  not  noticed. 


DOMESTIC     CHEMISTRY.  23d 

materials  for  bone-making.*  Soda  and  HC1  are  also  used 
in  baking.  By  heat  both  constituents  are  resolved  into 
H20,  C02,  and  NaCl.  The  H20  and  C02  raise  the  bread, 
while  the  common  salt  seasons  it.  There  is  a  difficulty 
in  procuring  pure  acid  and  in  mixing  the  ingredients  in 
their  combining  proportions.  Sal-volatile  (ammonium 
sesquicarbonate,  p.  135)  is  often  used  by  bakers  for  raising 
cake.  This  should  volatilize  into  two  gases,  H3N  and 
C02,  on  the  application  of  heat,  but  in  practice  a  portion 
is  commonly  left  hidden  in  the  cake,  and  may  be  detected 
by  the  odor.  Alum  is  often  employed  by  bakers  to 
whiten  bread  and  render  the  gluten  of  inferior  flour 
more  tenacious. 

Jfo&fHng  ^Sread.  —  By  toasting,  bread  becomes 
much  more  digestible,  as  the  starch  is  converted  largely 
into  dextrine,  which  is  soluble.  The  charcoal  which  may 
be  formed  when  the  heat  has  disorganized  the  bread  and 
driven  off  the  water,  also  acts  favorably  on  the  stomach 
by  absorbing  in  its  pores  noxious  gases,  as  in  "  crust- 
coffee." 

Cooking  ^Potatoes. — A  raw  potato  is  indigestible, 
but  by  cooking,  the  starch  granules  absorb  the  water  of 
the  potato,  burst,  and  make  it  "  mealy."  If  the  potato 
contains  more  H20  than  the  starch  can  imbibe,  it  is  called 
"  watery." 


*  It  is  doubtful  whether  ordinary  yeast-powders  or  cream  of  tartar  and  soda 
make  as  healthy  food  as  the  regular  process  of  fermentation.  There  is  fre- 
quently a  portion  of  the  powders  left  uncombined,  and  always  a  salt  formed 
which  may  perhaps  interfere  with  the  action  of  the  gastric  juice.  Sometimes, 
indeed,  we  find  biscuit  and  cake  yellow,  and  even  spotted  with  bits  of  saleratus  ; 
yet,  through  a  false  economy,  such  food  is  too  often  "  eaten  to  save  it." 


ORGANIC     CHEMISTRY. 


PRACTICAL    QUESTIONS. 

1.  How  would  you  prove  the  presence  of  tannin  in  tea? 

2.  How  would  you  test  for  Fe  in  a  solution  ? 

3.  Why  can  we  settle  coffee  with  an  egg  ? 

4.  How  would  you  show  the  presence  of  starch  in  a  potato  ? 

5.  Why  is  starch  stored  in  the  seed  of  a  plant  ? 

6.  Why  are  unbleached  cotton  goods  dark-colored  ? 

7.  Why  do  beans,  rice,  etc.,  swell  when  cooked  ? 

8.  Why  does  decaying  wood  darken  ? 

9.  Why  does  smoke  cure  hams  ? 

10.  How  would  you  show  that  C  exists  in  sugar  ? 

11.  Why  do  fruits  lose  their  sweetness  when  oATer-ripe  ? 

12.  Why  does  maple-sap  lose  its  sweetness  when  the  leaf  starts  1 

13.  Should  yeast  cakes  be  allowed  to  freeze  ? 

14.  Why  will  wine  sour  if  the  bottle  be  not  well  corked  ? 

15.  Why  can  vinegar  be  made  from  sweetened  water  and  brown 


paper 


16.  Why  should  the  vinegar-barrel  be  kept  in  a  warm  place  ? 

17.  Why  does  "  scalding  "  check  the  "  working  "  of  preserves  ? 

18.  Is  the  oxalic  acid  in  the  pie-plant  poisonous  ? 

19.  How  may  ink-stains  be  removed  ? 

20.  Why  is  leather  black  on  only  one  side  ? 

21.  Why  do  drops  of  tea  stain  a  knife-blade  ? 

22.  Why  will  not  coffee  stain  it  in  the  same  way  ? 

23.  Why  does  writing-fluid  darken  on  exposure  to  the  air  ? 

24.  What  causes  the  disagreeable  smell  of  a  smoldering  wick  ? 

25.  Why  does  ink  corrode  steel  pens  ? 

26.  How  does  a  bird  obtain  the  CaC03  for  its  egg  shells? 

27.  Why  will  tallow  make  a  harder  soap  than  lard  ? 

28.  Why  does  new  soap  act  on  the  hands  more  than  old? 

29.  What  is  the  shiny  coat  <5n  certain  leaves  and  fruits  ? 

30.  Why  does  turpentine  burn  with  so  much  smoke  ? 

31.  Why  is  the  nozzle  of  a  turpentine  bottle  so  sticky  ? 

32.  Why  does  kerosene  give  more  light  than  alcohol  ? 

33.  What  is  the  antidote  to  oxalic  acid  ?    Why  ? 

34.  Would  you  weaken  camphor  spirits  with  water? 

35.  What  is  the  difference  between  rosin  and  resin  ? 

36.  Why  does  skim-milk  look  blue  and  new  milk  white  ? 

37.  Why  does  an  ink-spot  turn  yellow  after  washing  with  soap  ? 


CONCLUSION.  237 


CONCLUSION. 

Chemistry  of  the  Stmbeam.  —  The  various  plant- 
products  of  which  we  have  spoken  in  Organic  Chemistry, 
when  burned,  either  in  the  body  as  food  or  in  the  air  as 
fuel,  give  off  heat.  This  was  garnered  in  the  plant  while 
growing,  and  came  from  that  great  source  of  heat — the 
sun.  Thus  all  vegetation  contains  the  latent  heat  of  the 
sunbeam,  ready  to  be  set  free  upon  its  own  oxidation. 
The  coal,  even,  derived  as  it  is  from  ancient  vegetation, 
hidden  away  in  the  earth,  is  thus  a  mine  of  reserved 
force.  Those  black  diamonds  we  use  as  fuel  become,  in 
the  eye  of  science,  crystallized  sunbeams,  fagots  of  force, 
ready  to  impart  to  us  at  any  moment  the  heat  of  some 
old  Carboniferous  day.  A  field  of  growing  wheat  reaches 
out  its  tiny  arms,  and  tangling  in  stalk  and  grain  the 
heat  of  sultry  mid-summer, 'retains  it  against  the  bleak 
December.  The  oil-well  spouts  not  alone  unsavory 
kerosene,  but  liquid  sunbeams,  the  gathered  store  of  a 
geologic  age.  As  we  warm  ourselves  by  our  fires,  or  sit 
and  read  by  our  oil  and  gas  lights,  how  strange  the 
thought  that  their  light  and  heat  streamed  down  upon 
the  earth  ages  ago,  were  absorbed  by  the  grotesque  leaves 
of  the  old  coal  forests,  and  kept  safely  stored  away  by  a 
Divine  care,  in  order  to  provide  for  our  comfort !  The 
present  warmth  of  our  bodies  all  came  from  the  same 
source — the  sun.  It  mostly  fell  in  the  sunbeams  of  last 
summer  upon  our  gardens  and  fields,  was  preserved  in 
the  potatoes,  cabbage,  corn,  etc.,  we  have  eaten  as  food, 


288  CONCLUSION. 

and  to-day  reappears  as  heat  and  motion.  Every  blow, 
every  breath,  and  every  step,  are  but  transformations  of 
solar  rays  and  can  be  estimated  in  sunshine. 

jf/ie  Sun  the  Source  of  (Power.  —  The  Sun 
warms,  enlivens,  and  animates  the  earth.  In  the  labora- 
tory of  the  leaf  he  produces  the  most  wonderful  chemical 
changes.  We  see  his  handiwork  in  the  building  of  the 
forest,  the  carpeting  of  the  meadow,  and  the  tinting  of 
the  rose.  On  the  ladder  of  the  sunbeam  water  climbs  to 
the  sky,  and  falls  again  as  rain.  The  very  thunder  of 
Niagara  is  but  the  sudden  unbending  of  the  spring  that 
was  first  coiled  by  the  sun  in  the  evaporation  from  the 
ocean.  Up  to  the  sun,  then,  we  trace  all  the  hidden 
manifestations  of  power.  Yet  the  force  that  produces 
such  intricate  and  wide-extended  changes  is  only  one 
twenty-three  hundred  millionth  part  of  the  tide  that 
flows  in  every  direction  from  this  great  central  orb.  But 
what  is  our  sun  itself  save  a  twinkling  star  beside  great 
suns  like  Sirius,  and  Regulus,  and  Procyon,  whose  bril- 
liancy in  the  far-off  regions  of  space  drowns  our  little  sun 
as  the  dazzling  light  of  day  does  the  smouldering  blaze 
of  some  wandering  hunter  ? 

Changes  of  Matter. — Chemical  changes  are  taking 
place  wherever  we  look — on  land  or  sea.  The  hard 
granite  crumbles  and  moulders  into  dust.  The  stout 
oak  draws  in  the  air  and  solidifies  it ;  takes  up  the  earth 
and  vitalizes  it ;  changes  all  into  its  own  structure,  and 
proudly  stands  monarch  of  the  forest.  But  in  time  its 
leaves  turn  yellow  and  sere ;  its  branches  crumble ;  itself 
totters,  falls,  and  disappears.  Our  bodies  seem  to  us  com- 
paratively stable,  but,  with  the  rock  and  the  oak,  they 
too  pass  away.  All  Nature  is  a  torrent  of  ceaseless 


CONCLUSION.  239 

change.  We  are  but  parts  of  a  grand  system,  and  the 
elements  we  use  are  not  our  own.  The  water  we  drink 
and  the  food  we  eat  to-day  may  have  been  used  a  thous- 
and times  before,  and  that  by  the  vilest  beggar  or  the 
lowest  earth-worm.  In  Nature  all  is  common,  and  no  use 
is  base.  Those  particles  of  matter  we  so  fondly  call  our 
own,  and  decorate  so  carefully,  a  few  months  since  may 
have  dragged  boats  on  the  canal,  or  waved  in  the  meadow 
as  grass  or  corn.*  From  us  they  will  pass  on  their  cease- 
less round  to  develop  other  forms  of  vegetation  and  life, 
whereby  the  same  atom  may  freeze  on  arctic  snows,  bleach 
on  torrid  plains,  be  beauty  in  the  poet's  brain,  strength 
in  the  blacksmith's  arm,  or  beef  on  the  butcher's  block. 
Hamlet  must  have  been  somewhat  more  of  a  chemist  than 
a  madman  when  he  gravely  assured  the  king  that  "  man 


*  The  truth  that  matter  passes  from  the  animal  back  to  the  vegetable,  and 
from  the  vegetable  to  the  animal  kingdom  again,  received,  not  long  since,  a  curi- 
ous illustration.  For  the  purpose  of  erecting  a  suitable  monument  in  memory 
of  Roger  Williams,  the  founder  of  Rhode  Island,  his  private  burying-ground  was 
searched  for  the  graves  of  himself  and  wife.  It  was  found  that  everything  had 
passed  into  oblivion.  The  shape  of  the  coffins  could  only  be  traced  by  a  black 
line  of  carbonaceous  matter.  The  rusted  hinges  and  nails,  and  a  round  wooden 
knot,  alone  remained  in  one  grave ;  while  a  single  lock  of  braided  hair  was 
found  in  the  other.  Near  the  graves  stood  an  apple-tree.  This  had  sent  down 
two  main  roots  into  the  very  presence  of  the  coffined  dead.  The  larger  root, 
pushing  its  way  to  the  precise  spot  occupied  by  the  skull  of  Roger  Williams,  had 
made  a  turn  as  if  passing  around  it,  and  followed  the  direction  of  the  backbone 
to  the  hips.  Here  it  divided  into  two  branches,  sending  one  along  each  leg  to 
the  heel,  when  both  turned  upward  to  the  toes.  One  of  these  roots  formed  a 
slight  crook  at  the  knee,  which  made  the  whole  bear  a  striking  resemblance  to 
the  human  form.  (These  roots  are  now  deposited  in  the  museum  of  Brown 
University.)  There  were  the  graves,  but  their  occupants  had  disappeared ;  the 
bones  even  had  vanished.  There  stood  the  thief— the  guilty  apple-tree—caught 
in  the  very  act  of  robbery.  The  spoliation  was  complete.  The  organic  matter— 
the  flesh,  the  bones,  of  Roger  Williams— had  passed  into  an  apple-tree.  The  ele- 
ments had  been  absorbed  by  the  roots,  transmuted  into  woody  fib  re,  which  could 
now  be  burned  as  fuel,  or  carved  into  ornaments;  had  bloomed  into  fragrant 
blossoms,  which  had  delighted  the  eye  of  passers-by,  and  scattered  the  sweetest 
perfume  of  spring ;  more  than  that— had  been  converted  into  luscious  fruit,  which, 
from  year  to  year,  had  been  gathered  and  eaten.  How  pertinent,  then,  is  the 
question,  "  Who  ate  Roger  Williams  ?" 


240  CONCLUSION. 

may  fish  with  the  worm  that  hath  eat  of  a  king,  and  eat 
of  the  fish  that  hath  fed  of  the  worm." 

Shakespeare  expresses  the  same  chemical  thought  when 
lie  says : 

"  Imperious  Caesar,  dead  and  turned  to  clay, 
Might  stop  a  hole  to  keep  the  wind  away. 
Oh  !  that  the  earth  which  kept  the  world  in  awe 
Should  patch  a  wall  to  expel  the  winter's  flaw  1" 

Or,  again,  when  he  makes  Ariel  sing : 

"  Full  fathom  five  thy  father  lies : 
Of  his  bones  are  coral  made  ; 
Those  are  pearls  that  were  his  eyes ; 
Nothing  of  him  that  doth  fade 
But  doth  suffer  a  sea  change 
Into  something  rich  and  strange." 

Ztife  and  1)ealh  are  thus  throughout  nature  com- 
mensurate with  and  companions  of  each  other.  Oxygen 
is  the  destroyer,  and  the  sunbeam  the  builder.  Oxygen 
tears  down  every  living  structure,  and  would  bring  all 
things  to  rest  in  ashes.  The  sunbeam  re-invigorates, 
rebuilds,  and  rescues  from  the  grasp  of  decay.  Though 
they  seem  to  be  antagonists,  oxygen  and  the  sunbeam 
really  work  in  harmony,  and  each  supplements  the  labor 
of  the  other.  Death  alone  makes  life  possible. 

Thus  we  have  traced  some  of  the  wonderful  processes 
by  which  this  World  has  been  arranged  to  supply  the 
varied  wants  of  man.  Wherever  we  have  turned,  we  have 
found  proofs  of  a  Divine  care  planning,  conforming,  and 
directing  to  one  universal  end,  while  from  the  commonest 
things  and  by  the  simplest  means  the  grandest  results 
have  been  attained.  Thus  does  Nature  attest  the  sublime 
truth  of  Eevelation,  that  in  all,  and  through  all,  and  over 
all,  the  Lord  God  omnipotent  reigneth. 


IV. 

A  p  p  e  n  6  i  x. 


NAMES    OF    CHEMICALS 


ACCORDING  TO 


THE  OLD  AND  THE  NEW  NOMENCLATURE. 


THE  NEW.  THE  OLD. 

1.  Ammonium  carbonate Carbonate  of  ammonia. 

2.  chloride Chloride  of  ammonium. 

3.  sulphate Sulphate  of  ammonia. 

4.  Antimony  sulphide Sulphide  (sulphuret)  of  antimony. 

5.  Barium  sulphate Sulphate  of  baryta,  or  Barytes. 

6.  Calcium  carbonate Carbonate  of  lime. 

7.  u         chloride Chloride  of  calcium. 

8.  "          hypochlorite Hypochlorite  of  lime. 

9.  "          oxide Lime. 

o.        u         phosphate Phosphate  of  lime. 

"         sulphate Sulphate  " 

"         sulphite Sulphite  " 

Carbon  disulphide Bisulphide  (bisulphuret)  of  carbon 

Carbonic  anhydride* Carbonic  acid. 

15.  Copper  nitrate Nitrate  of  copper. 

16.  "        oxide Oxide 

17.  "       sulphate Sulphate        " 

18.  Ferric  oxide Sesquioxide  of  iron. 

19.  "       hydrate Hydrated  sesquioxide  of  iron. 

20.  Ferric  disulphide Bisulphide  (bisulphuret)  of  iron. 

21.  Ferrous  sulphide Sulphide  (sulphuret)  of  iron. 

22.  Hydrogen  potassium  carbonate Bicarbonate  of  potash  (potassa). 

23.  u         protoxide  (water,  H2O) . .  Protoxide  of  hydrogen  (HO). 

24.  "         sodium  carbonate Bicarbonate  of  soda. 

25.  "          sulphide Sulphide  of  hydrogen.    • 

26.  Hyponitric  anhydride  (acid) Nitrous  acid. 

27.  Iron  disulphide Bisulphide  (bisulphuret)  of  iron. 

28.  "    sulphide Sulphide  (sulphuret)  of  iron. 

29.  "    sulphate Sulphate  of  iron,  or  Protosulphate  of  iron 

30.  Lead  acetate Acetate  of  lead. 

31.  u      carbonate  Carbonate  of  lead. 

32.  "      oxide Oxide  of  lead. 

*  See  note,  p.  29.    In  the  old  nomenclature  it  is  customary  to  apply  the  term 
acid  indifferently  to  the  hydride  (hydrous)  or  anhydride  (anhydrous). 


244  NAMES     OF     CHEMICALS. 

THE  NEW.  THE  OLD. 

33.  Lead  silicate Silicate  of  lead. 

34.  "     sulphide Sulphide  (sulphuret)  of  lead. 

35.  Magnesium  oxide Magnesia. 

36.  "  carbonate Carbonate  of  magnesia,  or  Magnesia. 

37.  u  sulphate Sulphate  of  magnesia. 

38.  Manganese  dioxide Binoxide  of  manganese. 

39.  Mercuric  chloride Chloride  of  mercury. 

40.  Mercurous  chloride Subchloride  of  mercury. 

41.  Mercuric  oxide Red  oxide  of  mercury. 

42.  Mercury  sulphide Sulphide  (sulphuret)  of  mercury. 

43.  Nitric  anhydride Anhydrous  nitric  acid. 

44.  Potassium  bromide Bromide  of  potassium. 

45.  "          carbonate Carbonate  of  potash. 

46.  4t          chlorate Chlorate  of  potash. 

47.  **          chloride Chloride  of  potassium. 

48.  "          cyanide Cyanide  of  potassium. 

49.  "          ferricyanide Ferricy anide  of  potash. 

50.  **          ferrocyanide Ferrocyanide  of  potash. 

51.  "          hydrate Hydrated  potash  (potassa),  or  Potash. 

52.  "  iodide Iodide  of  potassium. 

53.  "          nitrate Nitrate  of  potash. 

54.  "          permanganate Permanganate  of  potash. 

55.  "  sulphate Sulphate  of  potash. 

56.  Silicic  anhydride Anhydrous  silicic  acid. 

57.  Silver  chloride Chloride  of  silver. 

58.  "     cyanide Cyanide  of  silver. 

59.  "     iodide Iodide  of  silver. 

60.  "     nitrate Nitrate  of  silver. 

61.  "     sulphate Sulphate  of  silver. 

62.  Sodium  biborate Biborate  of  soda. 

63.  "       carbonate Carbonate  of  soda. 

64.  "       chloride Chloride  of  sodium. 

65.  "       hyposulphite Hyposulphite  of  soda. 

66.  4l       nitrate Nitrate  of  soda. 

67.  u       phosphate Phosphate  of  soda. 

68.  "       silicate Silicate  of  soda. 

69.  "       sulphate Sulphate  of  soda. 

70.  Sulphuric  anhydride Anhydrous  sulphuric  acid,  or  Sulphuric 

acid. 

71.  "        acid Hydrated   sulphuric  acid,  or  Sulphuric 

acid. 

72.  Sulphurous  anhydride Anhydrous  sulphurous  acid. 

73.  Tin  oxide Oxide  of  tin. 

74.  Zinc  oxide Oxide  of  zinc. 

75.  **     Sulphate Sulphate  of  zinc. 


SIMPLE  DIRECTIONS  POUT  EXPERIMENTS 

FOR     BEGINNERS. 


THE  following  simple  suggestions  will  enable  any  student  to 
perform  all  the  experiments  mentioned  in  this  work.  Many 
easy  illustrations  are  also  given  in  addition  to  those  named  in  the 
text.  The  Italic  figures  refer  to  the  pages  of  the  book,  and  the 
small  ones  to  the  number  of  the  experiment. 

18. — i.  Put  into  the  mortar  as  much  potassium  chlorate  as  will 
lie  upon  the  point  of  a  knife-blade,  and  half  as  much  sulphur. 
Grind  them  slowly  with  the  pestle  until  the  ingredients  are  thor- 
oughly mixed  and  distributed  over  the  bottom  of  the  mortar.  Hold 
the  mortar  so  that  the  loose  particles  cannot  fly  into  your  eyes,  nor 
the  flame  burn  your  clothes,  and  then  grind  heavily  with  the  pestle, 
when  rapid  detonations  will  ensue.  The  mixture  will  last  for  days. 
After  use,  clean  out  the  mortar  carefully  for  other  experiments. 
The  powder  can  be  wrapped  with  paper  into  a  hard  pellet  and  ex- 
ploded on  an  anvil  by  a  sharp  blow  from  a  hammer.  Sometimes 
small  bits  of  phosphorus  are  used  instead  of  sulphur.  Great  care 
is  then  necessary,  as  the  particles  of  burning  phosphorus  are  apt  to 
fly  to  some  distance. 

2.  Dissolve  40  grs.  of  common  soda  in  one  wine-glass  of  water, 
and  35  grs.  of  tartaric  acid  in  another.  On  being  poured  together 
in  a  goblet  they  will  violently  effervesce.  Use  a  glass  which  is  large 
enough  to  prevent  any  of  the  liquid  from  running  over  upon  the 
table.  Neatness  in  experiments  is  essential  to  perfection  and  often 
to  success.  At  the  close  of  this  illustration,  evaporate  the  solu- 
tion,* and  a  neutral  salt  will  result  (see  page  211). 

*  Pour  a  part  of  the  liquid  into  an  evaporating  dish,  and  place  this  on  the  tripod 
over  the  flame  of  the  spirit-lamp,  or  upon  a  hot  stove.  Heat  until  a  drop  of  the 
liquid  taken  out  on  the  end  of  a  glass  rod  and  put  on  a  bit  of  glass  will  crystal- 
lize as  soon  as  it  cools.  Then  set  the  dish  aside  to  cool,  when  crystals  will  soon 
begin  to  form.  In  this  connection  it  is  well  to  remark  that  a  cook-stove  will  be 


DIRECTIONS    ABOUT   EXPERIMENTS. 


22-3. — i.  A  few  drops  of  vinegar,  or  any  acid,  will  turn  the  pur- 
ple cabbage-solution  to  a  bright  red  ;  and  a  little  of  the  potash 
solution  to  a  deep  green.  Add  a  little  alcohol  to  the  red  solution 
to  keep  it  from  freezing,  and  bottle  for  use.  Dissolve  20  or  30  grs. 
of  the  litmus  in  an  oz.  of  water  ;  filter  and  bottle.  Dissolve  also  a 
stick  of  potash  in  4  oz.  of  water  ;  filter  and  bottle.  Fill  two  test-tubes 
nearly  full  of  water  ;  color  one  with  the  cabbage  solution  and  the 
other  with  the  litmus  solution.  To  each  add  alternately  a  few  drops 
of  the  potash  solution  and  of  oil  of  vitriol.  The  color  can  be 
changed  at  pleasure. 

A  pipette — a  glass-tube  with  a  bulb  in  the  middle  and  one  end 
drawn  to  a  point — will  be  found  convenient  for  dropping  liquids. 
In  lieu  of  this,  take  a  piece  of  glass-tubing,*  and  heating  the  end  in 
the  flame  of  the  spirit-lamp  (the  greatest  heat  is  near  the  tip),  seal 
the  openings.  This  will  readily  take  up  a  drop  upon  its  extremity, 
and  several  such  tubes  will  be  found  useful  for  stirring  liquids. 

27. — i.  Pulverize  one-half  an  ounce  of  potassium  chlorate  in  the 
mortar  very  carefully ;  stir  in  it  one-half  its  weight  of  black  oxide 
of  manganese  and  place  the  mixture  in  the  Florence  flask  :  fit  a 
cork  to  the  nozzle  ;  then  withdraw  the  cork,  and  with  a  round  file 
bore  a  hole  through  it  just  large  enough  f  to  admit  a  glass  tube 
bent  %  fts  shown  in  Figs.  2  or  10.  Return  the  cork  and  tube,  ar- 


found  of  great  use  in  chemical  experiments,  and  indeed  may,  in  the  laboratory, 
well  take  the  place  of  a  furnace.  The  oven  will  dry  apparatus  and  chemicals ; 
the  heat  is  sufficient  for  evaporating  solutions,  distilling  water,  etc.,  while  an 
excellent  sand  or  water-bath  may  be  readily  contrived. 

*  The  tube  may  be  cut  of  any  length.  Lay  it  upon  the  table,  and  with  a 
three-cornered  file  make  a  deep  scratch  where  you  wish  to  break  it ;  then  hold 
the  tube  in  both  hands,  placing  a  thumb  on  each  side  of  the  scratch,  and  with  a 
steady  pressure  the  glass  will  break  at  the  desired  point.  Two  tubes,  each  closed 
at  one  end,  may  also  be  obtained  very  easily  by  heating  a  piece  of  tubing  in  the 
flame  until  a  ring  of  the  glass  becomes  very  soft,  when  by  pulling  upon  the 
opposite  ends  of  the  tube,  the  heated  portion  will  be  drawn  out,  diminished  in 
size,  and  the  opening  closed.  A  little  practice  will  enable  the  student  to  do  this 
neatly  and  expertly.  Gas-jets  may  also  be  made  in  this  way  for  the  experiments 
illustrated  in  Figs.  12, 15,  16,  and  19. 

t  Whenever  corks  leak  gas  they  may  be  wrapped  with  thin  strips  of  wet 
paper  to  make  them  fit  more  tightly  ;  or  the  entire  nozzle  may  be  smeared  with 
tallow,  or  covered  with  sealing-wax,  if  heat  is  not  used.  In  that  case  a  little 
plaster-of- Paris  may  be  wet  up  and  quickly  applied. 

%  A  glass  tube  may  be  bent  at  any  point  by  softening  that  part  in  the  flame  of 
the  spirit-lamp.  Practice  alone  will  give  the  required  expertness.  The  follow- 
ing points  should  be  observed :  i.  Keep  the  tube  constantly  turning  between 
the  fingers  so  that  it  may  be  equally  heated  on  all  sides ;  2.  Do  not  twist  or  pull 


DIRECTIONS    ABOUT    EXPERIMENTS.    247 

range  the  apparatus  as  shown  in  the  figures,  and  apply  the  heat. 
This  must  be  done  very  cautiously  at  first,  holding  the  lamp  in  the 
hand  and  moving  it  around  so  that  the  flame  may  strike  all  the 
lower  part  of  the  flask,  and  thus  expand  it  uniformly.  Be  careful 
also  that  no  draft  of  cold  air  strikes  against  the  heated  retort.  The 
first  few  bubbles  of  gas  will  consist  mainly  of  the  air  contained  in 
the  flask,  and  should  not  be  caught.  When  the  gas  begins  to  pass 
over  freely,  diminish  the  heat.*  When  the  gas  ceases,  remove  the 
stopper  from  the  flask,  or  lift  the  end  of  the  tube  out  of  the  we  ter ; 
otherwise,  as  the  flask  COMO!S,  and  a  vacuum  is  formed,  the  water 
in  the  tub  will  set  back  into  the  flask  and  break  it.  When  the  retort 
is  nearly  cool,  pour  in  some  warm  water  to  dissolve  the  residuum, 
which  may  then  be  poured  out  and  the  flask  dried  for  future  use. 

Mg.  75. 


a — Copper  retort  ;  b — A  copper  tube  leading  from  it ;  c —  Tube  of  india-rubber 
to  convey  the  gas  to  a  gas-bag,  gasometer,  or  pneumatic  trough  ;  d— Gas-bag  ; 
e— Spirit-lamp. 

In  order  to  test  the  purity  of  the  materials,  and  thus  avoid  any 
danger  of  an  explosion,  it  is  well,  previous  to  putting  the  mixture 
in  the  flask,  to  place  a  little  in  an  iron  spoon  and  heat  it  over  the 
lamp.  If  the  gas  pass  off  quietly,  no  danger  need  be  apprehended. 
— Instead  of  bending  the  glass  tubing  it  may  be  cut  into  short 


the  tube  while  heating  ;  3.  Do  not  bend  it  until  very  soft ;  if  not  hot  enough  the 
elbow  will  be  flattened. 

*  The  gas  often  looks  cloudy,  owing  to  little  particles  of  the  salt  which  are 
carried  over  suspended  in  it  in  fine  powder ;  but  these  gradually  become  dissolved 
in  the  water. 


DIRECTIONS    ABOUT    EXPERIMENTS. 


lengths,  and  the  pieces  joined  by  short  bits  of  rubber  tubing,  as  in 
Figs.  10  and  13. 

The  advantage  of  this  is  that  the  flexible  joints  are  not  liable  to 
break,  and  the  apparatus  may  be  more  easily  moved.  Where  a 
large  quantity  of  0  is  to  be  made,  a  copper  retort  and  rubber  tubing 
will  be  found  cheap  and  convenient.  No  especial  care  is  then 
needed  in  managing  the  heat.  In  place  of  the  pneumatic  tub,  a 
pail  or  a  tin  pan  even  may  be  used,  letting  the  bottle  rest  on  a  shelf 
as  in  Fig.  10,  or  on  a  couple  of  bricks.  The  bottles  for  collecting 
the  gas  may  be  the  regular  "  deflagrating-jar  "  of  the  chemist,  or  the 
common  "  packing-bottle  "  of  the  druggist.  They  are  to  be  sunk  in 
the  water  of  the  pneumatic  tub  and  filled  ;  then  inverted  and  lifted 
upon  the  shelf,  carefully  keeping  the  lower  edge  of  the  bottle  un- 
der the  water.  The  bottles  may  also  be  filled  from  a  pitcher,  then 
closed  with  the  hand  or  a  plate,  and  quickly  inverted  and  placed  on 
the  shelf  in  the  tub  or  pan  ready  for  use.  As  soon  as  a  bottle  is 
filled  with  gas  a  plate  may  be  slipped  under  the  mouth,  and  thus, 
leaving  enough  water  in  the  plate  to  cover  the  lower  edge,  be  set 
aside  as  in  Fig.  2.  Gas  may  be  passed  from  one  jar  to  another  in 
the  manner  shown  in  Fig.  17. — While  the  gas  is  being  collected,  the 
water  from  the  bottles  which  are  filling  may  cause  the  tub  to  over- 
run ;  to  prevent  this,  arrange  a  siphon  to  carry  off  the  water  into  a 
pail  below  the  table. — When  a  jar  of  gas  is  wanted  for  use,  remove 
it  to  the  tub,  slip  a  plate  under  the  mouth,  or  simply  close  it  with 
the  hand,  and  lifting  the  jar  out,  carry  it  to  the  table  and  place  it 
mouth  upward.  Uncover  only  when  the  experiment  is  ready  to  be 
performed,  as  the  gas  will  slowly  diffuse. 

29-31. — i.  The  experiment  with  the  candle  may  be  very  strikingly 
performed  by  filling  a  common  fruit-jar  with  0,  and  another  with  N. 
The  covers  may  be  laid  loosely  on  top,  and  the  lighted  candle  passed 
quickly  from  one  to  another,  as  mentioned  in  note  on  page  43. 
The  candle  may  be  simply  stuck  on  the  end  of  a  bent  wire,  as  in 
Fig.  14,  but  it  is  much  neater  to  have  the  tinsmith  fit  a  little  cup 
for  its  reception,  as  shown  in  the  figure. 

2.  Worn-out  watch-springs  can  be  obtained  gratis  of  any  jew- 
eller, and  may  be  easily  straightened  by  slightly  heating  and  then 
drawing  them  between  the  fingers.  If  the  end  of  each  spring  be 
strongly  heated  and  then  pounded  with  a  hammer  on  any  smooth, 
hard  surface,  the  temper  may  be  drawn  and  the  edge  sharpened. 
Make  a  slit  with  a  knife  in  the  side  of  a  match,  into  which  insert 
the  edge  of  the  spring.  Take  a  piece  of  zinc  or  tin  large  enough  to 


DIRECTIONS    ABOUT    EXPERIMENTS. 


cover  the  mouth  of  the  jar  containing  the  oxygen,  and  make  a  hole 
through  it  with  a  nail.  Pass  the  other  end  of  the  spring  through 
this  hole,  and  then  through  a  thin  cork.  The  spring  is  now  ready 
for  burning.  The  metal  cover  will  prevent  the  flame  from  coming 
out  of  the  jar  and  burning  one's  hand,  and  the  cork  will  hold  the 
spring  in  its  place.  When  the  match  is  ignited,  and  then  lowered 
into  the  jar  of  0,  the  spring  should  not  reach  more  than  half-way  to 
the  bottom,  and  should  be  pushed  down  as  it  burns.  If  a  packing- 
bottle  be  used,  do  not  fill  it  quite  full  of,  gas,  as  then,  on  inverting, 
a  little  water  will  be  left  at  the  bottom  which  will  prevent  the  melt- 
ed globules  of  iron  from  breaking  the  glass. 

3.  If  brimstone  be  used  in  the  experiment  with  S,  and  it  fails  to 
light  readily,  pour  upon  it  a  few  drops  of  alcohol,  and  then  ignite. 

4.  If  you  have  not  a  "  deflagrating  spoon  "  —  a  little  metal  cup 
with  a  wire  attached  —  to  contain  the  phosphorus,  one  may  be  read- 
ily extemporized.     Hollow  a  small  piece  of  chalk  and  attach  a  wire 
to  it,  which  may  then  be  secured  to  a  metal  top,  as  in  the  case  of 
the  watch-spring.     This  need  not  be  pushed  down  into  the  jar  as 
the  burning  progresses.     Be  careful  to  cut  the  phosphorus  under 
water,  to  dry  it  carefully,  and  not  to  handle  it.     At  the  close  of  the 
experiment,  test  for  the  acid  formed  in  the  combustion.    The  fumes 
are  very  disagreeable,  and  should  not  be  inhaled  or  allowed  to 
escape  into  the  room. 

39.  —  i.  Put  in  an  evaporating-dish  a  little  starch  ;  cover  it  with 
water  in  which  a  few  crystals  of  potassium  iodide  have  been  dis- 
solved, and  heat.  Stir  the  liquid,  to  prevent  lumps.  When  cooked, 
immerse  in  the  paste  slips  of  white  blotting  or  clean  writing-paper. 
Use  while  moist.  Be  careful  not  to  heat  the  glass  tube  too  hot,  lest 
the  ether-vapor  may  ignite.  Keep  the  jar  well  filled  with  vapor  by 
frequently  shaking  it.  Lower  into  the  ozone  a  bit  of  silver-leaf 
moistened  with  water  ;  it  will  quickly  crumble  into  the  oxide. 

2.  Ozone  may  also  be  prepared  by  the  slow  oxidation  of  phos- 
phorus in  the  following  manner  :  Scrape  off  the  white  coating  of  a 
stick  of  phosphorus  under  water,  and  cut  the  cleansed  phosphorus 
into  pieces  12  or  15  millim.  long.*  Place  one  of  these  pieces  in  a 
wide-mouth  litre-bottle  full  of  air,  with  about  a  tea-spoonful  of 
water  at  the  bottom.  Close  the  mouth  of  the  bottle  with  a  glass 

*  The  metric  system  is  used  in  a  few  of  the  examples  which  follow,  in  order  to 
accustom  the  pupil  to  the  mode  which  is  adopted  by  all  scientific  men  in  their 
investigations  and  treatises.  Any  arithmetic  will  explain  the  meaning  of  the 
terms,  if  they  are  not  already  familiar  to  the  scholar.  (See  table,  p.  267.) 


250    DIRECTIONS    ABOUT   EXPERIMENTS. 

plate,  and  expose  the  whole  for  half  an  hour  to  a  temperature  of  15° 
or  20°  C.  Then  invert  the  neck  of  the  bottle  in  water,  and  allow 
the  phosphorus  to  fall  out.  Replace  the  glass  plate,  and  withdraw 
the  bottle  and  its  contents  from  the  water.  The  phosphorus  in  this 
experiment  undergoes  a  slow  oxidation,  during  which  a  little  ozone 
is  formed,  and  is  left  mixed  with  the  air  ;  but  the  ozone  will  be 
again  destroyed  if  it  is  left  too  long  with  the  phosphorus. 

3.  Add  to  the  bottle  of  air  which  has  been  ozonized  by  means  of 
phosphorus,  a  few  drops  of  a  very  dilute  blue  solution,  formed  by 
dissolving  powdered  indigo  in  strong  sulphuric  acid,  and  then 
diluting  it  with  water.  If  the  blue  liquid  be  shaken  up  with  the 
ozonized  air,  the  color  will  quickly  disappear. 

41. — i.  The  phosphorus  will,  without  the  aid  of  heat,  gradually 
remove  the  O  from  the  air,  forming  phosphorous  anhydride  (P20a), 
which  will  be  dissolved  by  the  water,  and  in  a  day  or  two  the  gas 
which  is  left  will  be  nearly  pure  N. 

4S. — To  make  the  iodide  of  nitrogen,  cover  a  few  scales  of  iodine 
with  strong  aqua-ammonia.  After  standing  for  a  half-hour,  pour 
off  the  liquid  and  place  the  brown  sediment  in  small  portions  on 
bits  of  broken  earthenware  to  dry.  They  may  then  be  carried  very 
carefully  to  the  class-room  and  exploded  by  a  slight  touch  of  a  rod 
or  even  a  feather. 

44' — i-  F°r  making  HN03  a  special  apparatus  is  necessary  for 
complete  success.  The  Florence  flask  may,  however,  be  used,  and 
the  heat  of  the  spirit-lamp  will  be  sufficient.  Use  equal  weights  of 
sodium  nitrate  and  strong  sulphuric  acid.  A  free  circulation  of  air 
is  necessary.  Nitrate  of  potash  will  answer  in  place  of  the  sodium 
salt.  The  fumes  may  be  caught  in  an  evolution-flask,  which  is 
Ikept  cool  by  a  towel  frequently  wet.  When  the  retort  is  partially 
cooled,  at  the  conclusion  of  the  process,  pour  in  a  little  warm 
water,  to  dissolve  the  potassium  sulphate,  otherwise  the  retort  may 
break  by  the  crystallization  of  the  salt. 

46. — i.  A  special  apparatus  is  necessary  both  for  preparing  and 
inhaling  nitrous  oxide  safely.  This  consists  of  a  glass  retort — as 
shown  in  the  cut — a  wash-bottle,  and  in  addition  a  gas-bag  of  from 
twenty  to  fifty  gallons  capacity  for  storing  the  gas,  and  a  smaller 
bag  of  from  three  to  five  gallons,  with  a  wide,  wooden  mouth-piece 
for  inhalation.  It  is  well  to  pass  the  gas  through  a  large  wash-bottle 
half  full  of  H20,  as  shown  in  Fig.  13,  thence  by  a  rubber  tube  directly 
into  the  large  gas-bag.  The  utmost  care  should  be  taken  both  in 
preparing  and  administering  this  gas,  as  other  oxides  of  nicrogen 


DIRECTIONS    ABOUT    EXPERIMENTS. 

are  liable  to  be  present.  Before  preparing  the  gas,  pour  into  the 
bag  a  couple  of  gallons  of  H2O  :  by  standing  over  which  it  will  be 
purified  in  a  few  hours.  When  about  to  administer  the  gas,  let  the 
subject  grasp  his  nose  firmly  between  his  thumb  and  forefinger ; 
then,  inserting  the  wooden  mouth-piece,  be  careful  that  he  does  not 
inhale  any  of  the  external  air,  but  takes  full,  deep  breaths  in  and 
out  of  the  gas-bag.  Watch  the  eye  of  the  subject,  and  notice  the 
influence  of  the  gas.  Commonly,  the  best  effect  is  not  reached 
until  he  begins  to  surge  backward  and  forward.  Great  care  is 
necessary,  and  no  one  should  ever  inhale  the  gas  who  is  not  in 
good  health,  who  is  troubled  with  a  rush  of  bipod  to  the  head,  any 
lung  or  heart  disease,  or  is  of  a  plethoric  habit. 

2.  Fill  a  small  jar  with  the  gas,  and  thrust  into  it  a  splinter  of 
wood  the  end  of  which  is  glowing  brightly  ;  it  will  burst  into  flame. 

3.  Place  some  S  in  a  deflagrating-spoon  ;  kindle,  and  when  burn- 
ing briskly  lower  into  the  gas  ;  it  will  burn  with  a  pale  rose-colored 
flame. 

4.  Half  fill  a  test-tube  with  gas,  over  water.     Close  the  tube 
under  water  firmly  with  the  thumb,  and  then  agitate  the  water  and 
gas  together.    On  removing  the  thumb  under  water,  a  considerable 
rush  of  water  into  the  tube  will  occur,  as  the  gas  is  soluble  in  about 
its  own  volume  of  cold  water.     By  this  circumstance  the  gas  is 
easily  distinguished  from  0. 

5.  To  show  the  effect  of  HN03  upon  the  metals,  procure  bits  of 
tin  and  copper  from  the  tinsmith.     Place  the  copper  clippings  in 
the  evolution-flask  (a,  Fig.  n).     Pour  into  the  flask  enough  warm 
water  to  cover  the   lower  end  of  the  funnel   tube,  which   should 
nearly  reach  the  bottom.     Then  add  the  acid  gradually. 

jflt — When  a  jar  is  filled  with  the  NO  it  may  be  lifted  out  of  the 
H.20  and  inverted,  when  the  N02  will  pass  off  in  blood-red  clouds. 
If  the  jar  be  left  in  the  cistern  and  one  edge  be  lifted  so  as  to  admit 
a  bubble  of  air,  red  fumes  will  fill  the  jar.  By  standing  a  moment 
the  water  will  absorb  the  red  vapor.  The  process  may  be  repeated 
several  times  with  the  remaining  gas.  The  variation  of  this  experi- 
ment described  in  the  note  on  page  47  will  be  found  very  interest- 
ing. The  change  of  color  produced  by  mixing  nitric  oxide  with 
any  gas  containing  free  oxygen,  often  affords  a  convenient  means 
of  detecting  small  quantities  of  oxygen  when  present  in  admixture 
with  other  gases,  such,  for  instance,  as  coal-gas. 

48. — I.  Mix  intimately  3  grams  of  fine  iron  filings  in  a  mortar 
with  0.2  gram  of  caustic  potash ;  introduce  the  mixture^into  a  test- 


DIRECTIONS    ABOUT    EXPERIMENTS. 


tube,  to  the  mouth  of  which  a  cork  and  a  bent  tube  are  attached 
Heat  the  mixture  over  the  spirit-lamp  ;  gas  will  escape,  and  maybe 
collected  over  water  in  a  test-tube.  It  burns  with  flame,  and  con- 
sists of  H.  At  a  high  temperature,  the  Fe  displaces  H  from  the 
caustic  potash  :  Fe  +  2KHO  =  FeO  +  K20  +  H2. 

Mix  3  grams  of  iron  filings  intimately  with  0.2  gram  of  nitre. 
Heat  the  mixture  and  collect  the  gas  as  before  :  it  will  not  burn, 
does  not  render  lime-water  milky,  and  is,  in  fact,  N.  The  Fe  has 
combined  with  the  0  of  the  nitre,  forming  potash  and  liberating  N  : 


Mix  6  grams  of  iron  filings  with  0.2  gram  of  caustic  potash  and 
0.2  gram  of  nitre,  and  heat  the  mixture  in  a  tube.  The  gas  which 
now  comes  off  has  the  pungent  smell  of  hartshorn  ;  it  is  strongly 
alkaline,  and  immediately  restores  the  blue  color  of  reddened  lit- 
mus. In  the  reaction  which  takes  place,  the  H  and  the  N,  at  the 
moment  that  each  is  set  free,  combine,  and  form  H3N. 

2.  Place  a  little  solution  of  litmus,  feebly  reddened  by  the  addi- 
tion of  a  drop  or  two  of  acid,  in  a  basin  ;    carefully  raise  the  flask 
full  of  ammonia  gas  from  the  gas-delivering  tube  ;   close  the  flask 
with  the  thumb,  plunge  the  mouth  under  the  solution  of  litmus,  and 
withdraw  the  thumb  :  the  liquid  will  rush  rapidly  into  the  flask,  the 
ammonia  gas  will  be  absorbed,  and  the  red  liquid  will  become  blue. 

3.  Boil  a  fluid-oz.  of  H3N  in  a  flask  provided  with  a  cork  and 
tube,  as  shown  in  Fig.  12  ;   the  gas  will  come  off  freely.     Apply  a 
light  to  the  jet  :  it  will  not  burn  readily,  but  a  pale  greenish  flame 

will  play  over  the  top 
of  the  light.  Place 
the  tube  from  which 
the  gas  is  escaping 
in  a  bottle  of  0,  and 
then  apply  a  light  :  it 
will  now  burn  with  a 
green  flame. 

50.  —  i.  For  prepar- 
ing H  the  apparatus 
shown  in  Fig.  13   is 
very  convenient.  The 
A  Hydrogen  Generator.  wash-bottle,  d,  is    ne- 

cessary  only  when  it 

is  desired  to  purify  the  gas  for  inhaling.     A  common  junk-bottle, 
fitted  with  a  cork  and  a  glass  tube,  will  answer  for  all  ordinary 


•  76' 


DIRECTIONS    ABOUT    EXPERIMENTS.     253 

experiments,  but  a  "hydrogen  generator,"  as  sold  by  apparatus 
dealers,  is  much  more  satisfactory.  The  Zn  for  making  H  should 
be  granulated.*  This  is  easily  done  by  melting  the  Zn  in  an  iron 
ladle,  and  pouring  the  metal  slowly  from  a  little  height  into  a  basin 
of  water.  Water  may  be  poured  into  the  flask  until  the  lower  end 
of  the  funnel  is  covered  before  adding  the  acid.  The  flow  of  gas 
may  be  regulated  by  additions  of  acid,  as  may  be  wanted.  One 
part  of  acid  to  10  or  12  of  water  will  liberate  the  gas  rapidly.  If 
too  much  H2SO4  be  added  the  liquid  is  apt  to  froth  over. 

In  experimenting  with  H,  great  care  must  be  used  not  to  ignite 
the  jet  of  gas  until  all  the  common  air  has  passed  out  of  the  flask  ; 
otherwise  a  severe  explosion  will  ensue.  It  is  a  safe  precaution  to 
test  the  gas  by  passing  it  in  bubbles  up  through  H20,  and  igniting 
them  at  the  surface  ;  the  force  of  the  combustion  will  indicate  if 
there  be  any  danger.  H  must  not  be  kept  in  bags  for  any  great 
length  of  time,  as  the  air  will  gradually  force  itself  in,  and  the  gas 
will  partly  pass  out  by  the  law  of  diffusion,  thus  forming  a  mixture 
which  it  is  dangerous  to  ignite. 

2.  The  gases  may  be  mixed  in  the  following  manner  :  Fit  a  good 
cork  into  the  neck  of  a  large  jar,  and  pass  through  it  a  tube  5 
centim.  long.  Bind  a  short  piece  of  rubber  tubing  firmly  to  the 
tube,  and  close  this  elastic  tube  with  a  small  screw-vice.f  Fill  the 
;'ar  with  wafer  over  the  pneumatic  tub.  Fill  a  small  jar  which  will 
hold  about  half  a  litre  with  0,  and  transfer  it,  as  shown  in  Fig.  17, 
lo  the  large  jar.  Fill  the  same  jar  with  H,  and  transfer  it  to  the  large 
jar.  Repeat  the  operation  with  the  H,  so  as  to  obtain  in  the  larger 
jar  a  mixture  of  half  a  litre  of  0  and  I  litre  of  H.  Having  previously 
softened  a  thin  bladder  by  soaking  it  in  water,  tie  into  the  neck  of 
it  a  glass  tube  5  centim.  long  ;  then  adjust  to  the  projecting  portion 
a  piece  of  rubber  tubing  provided  with  another  nipper-tap.  Press 
the  air  out  of  the  bladder  ;  connect  by  means  of  a  short  piece  of 
glass  tubing  the  two  pieces  of  rubber  tube  ;  depress  the  jar  in  the 
pneumatic  tub,  and  then  open  each  nipper-tap.  The  gas  will  now 
pass  into  the  bladder ;  if  it  does  not,  press  the  jar  deeper  into  the 
water  ;  close  both  nipper-taps,  and  remove  the  bladder.  Now  place 
the  end  of  the  tube  attached  to  the  bladder  under  some  soap-suds, 

*  If  the  zinc  scraps  obtained  at  a  tinsmith's  are  used,  this  will  be  unnecessary, 
as  they  may  be  readily  cut  into  shreds. 

t  Small  vices,  or  u  nipper-taps,"  as  they  are  called,  are  sold  for  this  purpose. 
They  are  cheaper  than  stop-cocks,  and  answer  every  purpose.  In  lieu  of  these, 
common  spring  clothes-pins  may  be  used. 


254     DIRECTIONS    ABOUT    EXPERIMENTS. 

and  force  out  the  mixed  gases  by  squeezing  the  bladder,  so  as  to 
make  a  lather.  Carefully  remove  the  bladder  to  a  distance,  and  then 
apply  a  light  to  the  froth  of  soap-suds.  A  loud  explosion  will  im- 
mediately follow. — A  clay  tobacco-pipe  may  be  attached  to  the  gas- 
bag by  means  of  a  bit  of  rubber  tubing.  Dip  the  pipe-bowl  into 
the  soap-suds,  and  lifting  it  out,  blow  a  bubble  with  the  mixed 
gases,  and  then  detach  it  by  a  quick  motion.  When  the  gas-bag  is 
removed,  ignite  the  bubble,  which  will  explode  sharply.  If  bubbles 
be  blown  with  H  alone,  they  will  rapidly  rise,  and  if  out  of  doors, 
will  float  to  a  great  distance. — If  one  has  a  large  rubber  gas-bag 
with  stop-cock  and  rubber  tubing,  and  a  glass  receiver  fitted  with 
a  stop-cock  on  top,  these  may  be  attached  and  the  gases  measured 
in  the  receiver  and  then  passed  directly  into  the  bag.  Such  appa- 
ratus, though  convenient,  is  not  necessary  to  illustrate  the  proper- 
ties of  the  gases. 

59. — i.  Grind  in  a  mortar  50  or  60  grams  of  sodium  sulphate 
with  about  twice  its  weight  of  water  at  15°  C.  The  water  will  dis- 
solve a  considerable  portion,  but  not  the  whole  of  the  salt.  Pour 
this  saturated  solution  into  a  flask,  and  warm  it  gently  ;  it  will  now 
dissolve  50  grams  more  of  the  salt  without  difficulty.  Allow  the 
solution  to  cool  down  to  the  temperature  of  the  air,  say  15°  C. : 
long  four-sided  needles  will  crystallize  from  the  liquid.  Pour  off 
the  liquid,  and  dry  the  crystals  by  pressing  them  between  a  few 
folds  of  blotting-paper.  When  they  appear  to  be  dry,  put  a  small 
quantity  of  the  crystals  into  a  test-tube,  and  apply  a  gentle  heat  : 
the  salt  will  liquefy,  and  on  continuing  to  apply  the  heat  a  large 
quantity  of  water  will  be  driven  off,  and  a  dry,  white  powder  will 
be  left  in  the  tube. 

2.  Take  some  of  the  fresh  crystals  of  sodium  sulphate  ;   let  them 
lie  exposed  on   a  piece  of  blotting-paper  for  two  or  three  days. 
They  will  gradually  lose  their  water,  and  crumble  down,  or  effloresce 
into  a  white  powder. 

3.  Select  a  thin,  porcelain  dish  which  will  hold  60  or  80  cub.  cm. ; 
place  it  in  one  pan  of  the  balance,  and  trim  a  piece  of  lead  until, 
when  placed  in  the  other  scale-pan,  it  will  counterpoise  the  dish. 
Measure  off  a  quarter  of  a  litre  of  spring-water,  and  pour  some  of 
it  into  the  weighed  dish ;  place  it  over  a  very  small,  gas  flame,  so  as 
to  evaporate  the  H2O  gently  without  allowing  it  to  boil  ;   add  the 
rest  of  the  H20  from  time  to  time  until  it  has  completely  evapo- 
rated.     Dry  the    salts  thus  obtained,  and  weigh  what  is  left  as 
accurately  as  you  can.     By  multiplying  this  quantity  by  4  you  will 


DIRECTIONS    ABOUT    EXPERIMENTS. 


obtain  the  amount  of  soluble  solid  substances  per  litre  which  that 
particular  specimen  of  water  contained.  This  is  the  basis  of  the 
plan  which,  with  many  additional  precautions,  is  adopted  for  deter- 
mining the  quantity  of  salts  in  the  process  of  analyzing  waters  to 
be  used  for  drinking  or  manufacturing  purposes. 

66.  —  i.  Small  paste-diamonds  may  be  obtained  of  a  jeweller,  to 
illustrate  the  forms  of  cutting  the  diamond. 

Mg.  77. 


69. — i.  Place  a  filtering  paper  in  the  glass  funnel,*  and  in  it  a 
couple  of  ounces  of  bone-black  or  finely-powdered  charcoal. 
Filter  through  it  water  colored  with  ink,  litmus,  or  any  other  im- 
purities. In  pouring  the  liquid  into  the  filter,  hold  a  glass  rod 
against  the  edge  of  the  pouring  vessel,  so  as  to  direct  the  stream 
into  the  funnel.  The  funnel  may  be  placed  in  the  nozzle  of  a 
bottle,  but  must  not  fit  closely.  A  bit  of  wood  or  a  thread  inserted 
between  the  stem  of  the  funnel  and  the  nozzle  will  leave  an  open- 
ing sufficient  for  the  egress  of  the  air. 

2.  Slip  a  piece  of  freshly  burned  charcoal  under  the  edge  of  a 
long  tube  previously  filled  with  dry  ammonia  gas,f  and  standing 
over  Hg.     The  charcoal  will  quickly  absorb  the  H;,N  ;  the  whole  of 
the  gas,  if  pure,  will  disappear,  and  the  Hg  will  fill  the  tube. 

3.  Weigh  a  piece  of  freshly  burned  charcoal  as  soon  as  it  is  cold  ; 
leave  it  exposed  to  the  air  for  twenty-four  hours,  and  weigh  it 
again  ;  it  will  be  found  to  be  heavier.    Place  the  charcoal  in  a  glass 


*  In  order  to  prepare  this  filter,  fold  a  square  of  paper,  as  shown  in  Fig.  77, 
first  into  halt,  and  then  again  into  a  quarter  of  its  first  size  (&)  •  cut  off  the  edges 
in  the  direction  of  the  dotted  line  shown  in  the  left-hand  figure  («),  open  out  the 
folded  paper  (c),  and  drop  it  into  a  funnel  a  little  larger  than  the  paper  cone. 

t  The  gas  may  be  dried  by  passing  it  through  a  tube  filled  with  pieces  of  cal- 
cium chloride  (see  Fig.  16),  obtained  in  making  CO2.  (See  page  74.) 


256     DIRECTIONS    ABOUT    EXPERIMENTS. 

tube,  and  heat  it  over  a  lamp  ;  moisture  will  be  driven  off,  and  will 
become  condensed  on  the  cold  sides  of  the  tube. 

4.  Shake  up  some  stagnant   water   which  has  been  kept  till  it 
smells  offensively,  with  a  little  powdered  charcoal.     In  an  hour  it 
will  have  lost  all  its  disagreeable  odor. 

5.  Mix  in  a  mortar  twenty  grams  of  litharge  with  forty  grams  of 
NaCI  and  one  gram  of  powdered  charcoal ;  cover  with  a  little  more 
salt,  and  place  the  mixture  in  a  small,  clay  crucible  ;  heat  it  to  bright 
redness  in  the  fire.     When  the  mixture  is  melted,  take  the  crucible 
out  of  the  fire  and  let  it  cool.     When  quite  cold,  break  the  crucible, 
and  a  bead  of  Pb  will  be  found  at  the  bottom,  under  the  melted  salt, 
the  C  having  taken  the  O  from  the  PbO. 

6.  Select  a  small  stick  of  charcoal,  and  with  the  point  of  a  knife 
make  a  small  cavity  of  the  size  of  a  split  pea  near  one  end.     Put 
a  little  white  lead  in  the  cavity,  and  heat   it   strongly  before  the 
blowpipe  in  the  reducing  flame.     A  little  bead  of  lead  will  easily 
be  obtained,  surrounded  by  a  border  of  yellow  lead  oxide.     The 
lead  will  flatten  under  the  hammer. 

7.  Place  in  a  cavity  in  another  piece  of  charcoal  a  small  fragment 
of  copper  oxide,  with  about  its  own  bulk  of  sodium  carbonate  to 
act  as  a  "  flux."     The  metal  will  require  a  stronger  heat,  but  may 
be  reduced  in  like  manner.     If  the  little  bead  be  placed  between 
two  folds  of  paper  it  may  be  flattened  with  the  hammer,  and  will 
show  the  red  color  of  copper. 

74-6 — i.  Break  some  marble  into  small  bits  ;  place  them  care- 
fully in  the  evolution-flask,  and,  inserting  the  cork  and  tube,  pour 
in  HCI  slowly.  The  gas,  on  account  of  its  weight,  may  be  passed 
directly  into  a  bottle  or  jar. 

2.  Lower  a  lighted  candle  into  a  jar  of  the  gas,  or,  placing  the 
candle  in  an  empty  jar,  pour  the  gas  into  the  jar,  as  if  it  were 
water.    Test  the  acid  with  blue  litmus-paper. 

3.  Place  a  piece  of  lime  as  large  as  an  egg  in  a  pint  of  water  ;  let 
it  stand  over  night ;    pour  off  the  clear  liquid :  it  is  lime-water. 
Place  a  little  in  a  tumbler  and  breathe  through  it  by  means  of  a 
tube,  or  pass  a  current  of  C03  from  the  evolution-flask  until  the 
liquid,  at  first  milky,  clears. 

4.  Breathe  through  a  tube  into  an  empty  bottle.     Lower  into  it  a 
lighted  candle — it  will  be  immediately  extinguished.    Pour  in  some 
lime-water,  shake  it  thoroughly  and  it  will  become  milky. 

5.  Twist  a  wire  around  the  neck  of  a  small,  wide-mouthed  vial,  to 
answer  as  a  bucket.     Lower  it  by  the  wire  into  a  jar  of  CO2,  our 


DIRECTIONS    ABOUT    EXPERIMENTS.     257 

ideal  well  foul  with  the  gas.     Raise  it  again,  and  test  for  the  C02  by 
means  of  a  lighted  match.  The  bucket  will  be  found  full  of  the  gas. 

6.  Balance  a  large  paper-bag  or  box  on  a  delicate  pair  of  scales, 
or  in  any  simple  manner  one's  ingenuity  may  suggest.    Empty  into 
the  box  a  large  jar  of  C02,  and  the  box  will  quickly  descend. 

7.  Arrange  little  wax-tapers  in  a  wooden  or  pasteboard  trough, 
as  on  page  75.     Light  them,  and  then  pour  in  at  the  top  a  bottle  of 
carbonic  acid  gas.     If  the  proper  slant  is  given  to  the  trough,  all 
the  candles  will  be  extinguished. 

80. — i.  Dry  some  potassium  ferrocyanide,  K4FeCy6,  3H20  (prus- 
siate  of  potash),  till  it  crumbles  down  to  a  white  powder.  Mix 
5  grams  of  this  with  50  c.  c.  of  oil  of  vitriol  in  a  Florence  flask  ; 
adjust  a  cork  and  a  wide,  bent  tube  to  the  mouth  of  the  flask,  and 
heat  the  mixture.  The  CO  will  come  off  very  quickly,  and  will 
burn  with  a  blue  flame. 

82. — i.  Introduce  into  a  retort  which  will  hold  a  litre,  30  c.  c.  of 
alcohol  and  60  c.  c.  of  oil  of  vitriol.  Heat  the  mixture,  and  collect 
the  gas  over  water  ;  continue  the  experiment  until  the  mass  black- 
ens and  swells  up  considerably.  The  product  consists  at  first 
chiefly  of  olefiant  gas,  mixed  with  ether-vapor ;  but  towards  the 
end  it  becomes  mingled  with  SO2.  Pass  it  through  a  solution  of 
potash,  using  a  wash-bottle  as  shown  in  Fig.  13,  and  then  collect  in 
the  gas-bag.  Fit  a  piece  of  glass  tubing,  drawn  to  a  fine  point  at 
one  end,  to  the  stop-cock  of  the  gas-bag,  by  means  of  a  bit  of  the 
rubber  tubing.  On  turning  the  stop-cock  and  forcing  out  the  gas, 
it  may  be  ignited,  when  it  will  burn  with  a  clear  white  light. 

2.  Mix  with  twice  its  bulk  of  O  and  explode  in  soap-bubbles.    It 
produces  a  greater  noise  even  than  the  "  mixed  gases."    Great  care 
must  be  taken  not  to  let  the  light  approach  the  gas-bag  containing 
the  mixture. 

3.  At  the  close  of  the  first  experiment  perform  the  one  described 
in  the  note  on  page  89.     A  small  piece  of  wire-gauze,  four  to  six 
inches  square,  for  this  purpose  can  be  purchased  of  any  tinsmith. 
If  you  do  not  force  the  gas  out  too  rapidly,  you  will  be  able  to  burn 
it  on  either  side  of  the  gauze  at  pleasure. 

4.  Place  on  top  of  the  gauze  a  piece  of  camphor-gum.     Ignite  it, 
and  the  flame  will  not  pass  through  to  the  lower  side.    Then  ignite 
on  the  lower  side,  and  extinguish  the  flame  on  the  upper  side. 

84. — i.  Fit  a  cork  to  a  small  test-tube.  Take  out  the  cork,  and 
pass  through  it  a  bit  of  glass  tubing  drawn  to  a  fine  point  at  one  end, 
so  as  to  act  as  a  gas-burner.  Place  in  the  tube  fifteen  or  twenty 


258     DIRECTIONS    ABOUT    EXPERIMENTS. 

grains  of  mercury  cyanide  ;  replace  the  cork  and  heat  over  a  spirit- 
lamp.  The  test-tube  may  be  supported  by  a  strip  of  thick  paper 
twisted  around  it  at  the  top.  Move  the  tube  to  and  fro  through  the 
flame  at  first,  until  it  becomes  fully  heated  ;  hold  the  tube  inclined 
and  not  perpendicular,  letting  the  flame  strike  the  side  rather  than 
the  bottom.  When  the  gas  begins  to  come  off,  it  may  be  ignited. 

91. — i.  The  compound  blow-pipe  with  gasometers,  as  shown  in 
Fig.  38,  is  the  most  serviceable  apparatus.  If  gas-bags  are  used, 
the  one  for  H  should  be  twice  the  size  of  the  one  for  0.  A  board 
should  be  laid  on  each  bag,  upon  which  weights  may  be  placed, 
when  ready  for  use,  so  as  to  force  out  the  gas  steadily.  Turn  the 
stop-cock  so  that  the  H  will  pass  out  twice  as  fast  as  the  0.  Always 
ignite  the  H  first,  and  then  turn-on  the  O  slowly  until  the  best  effect 
is  produced.  If  gasometers  are  used,  press  the  inner  receivers 
down  to  the  bottom,  and  then  pour  in  water  until  it  reaches  nearly 
the  top.  The  rubber  pipes  may  then  be  attached  to  the  hydrogen 
or  oxygen  apparatus,  and  the  gases  passed  directly  into  the  gas- 
ometer. Proper  pressure  is  produced,  when  the  jet  is  to  be  ignited, 
by  unloosing  the  strings  from  the  inner  receivers,  and  thus  taking 
off  the  "lift"  of  the  weights  which  equipoise  them.  Additional 
pressure  is  secured  by  bearing  down  upon  the  receivers.  All  the 
metals  burn  in  the  blow-pipe  flame  with  their  characteristic  colors. 
Narrow  slips  should  be  prepared  for  this  purpose.  A  mirror,  and 
a  cup  for  holding  the  chalk,  are  necessary  to  show  the  lime-light. 
A  piece  of  hard  chalk  or  lime,  whittled  to  about  the  size  of  a  pencil, 
may  be  held  in  the  flame  to  illustrate  the  principle. 

99. — 1$  To  a  small  gas-jar  fit  a  good  cork,  through  which  pass  a 
test-tube  as  shown  in  Fig.  42.  Place  the  jar  in  a  large  beaker- 
glass  or  open-mouthed  bottle,  filled  with  spring  water,  which  has 
been  mixed  with  a  fourth  of  its  bulk  of  a  solution  of  carbonic  acid  in 
water.  Fill  the  tube  with  water,  and  place  it  in  the  neck  of  the  jar, 
having  introduced  a  few  sprigs  of  mint  or  the  leafy  branches  of  any 
succulent  plant ;  then  expose  for  an  hour  or  two  in  direct  sunshine. 
Bubbles  of  gas  will  be  seen  studding  the  leaves  ;  and  on  shaking 
the  jar  they  will  become  detached,  and  will  rise  into  the  test-tube. 
After  a  time  the  cork  and  tube  may  be  withdrawn,  keeping  the 
mouth  of  the  tube  beneath  the  surface  of  the  water ;  then  close  it 
with  the  thumb,  turn  the  tube  mouth  upwards,  and  test  the  gas  with 
a  glowing  splinter.  The  wood  will  burst  into  a  blaze,  showing  that 
the  gas  consists  mainly  of  0. 

102. — i.  Put  in  the  flask  two  ounces  of  NaCl  and  an  ounce  and  a 


DIRECTIONS    ABOUT    EXPERIMENTS.      259 

half  of  Mn02.  Pour  on  enough  water  to  reduce  the  mixture  to  a  thin 
liquid.  Shake  the  flask  until  the  whole  interior  is  moistened. 
Insert  the  cork  and  delivery-tube  ;  the  middle  bottle  (B),  shown  in 
Fig.  43,  is  not  necessary.  Fill  the  pneumatic  tub*  with  warm  water, 
using  as  small  a  quantity  as  possible,  since  water  absorbs  the  gas. 
Pour  in  an  ounce  of  H2S04  through  the  funnel-tube  (F),  or  directly 
at  the  nozzle,  by  removing  the  ground  stopper,  if  a  kind  of  flask 
be  used  which  has  one.  The  gas  will  come  off  at  once,  even  before 
the  heat  is  applied.  Collect  the  gas  in  bottles  and  use  directly,  if 
convenient,  otherwise  put  corks  in  them  and  rub  the  nozzles  well 
with  tallow.  Pass  the  gas  through  a  tumbler  of  cold  water ;  this 
will  form  chlorine-water,  which  should  be  bottled  and  kept  in  a 
dark  place. 

2.  Plunge  a  lighted  taper  into  the  gas  :    it  will  burn  feebly,  with 
a  red,  smoky  flame. 

3.  Place  a  piece  of  dry  phosphorus  in   a  copper  deflagrating- 
spoon  ;   introduce  it  into  a  bottle  of  Cl :  the  phosphorus  will  take 
fire,  and  burn  with  a  pale  greenish  flame,  while  suffocating  fumes 
of  phosphoric  chloride  (PC15)  are  formed. 

4.  Dip  a  strip  of  blotting-paper  into  oil  of  turpentine  ;  plunge  it 
into  a  jar  of  Cl :  it  will  immediately  burst  into  flame,  while  a  dense 
black  smoke  is  given  off. 

5.  Powder  some  metallic  Sb  finely  in  a  mortar,  and  sprinkle  into 
a  jar  of  Cl :   it  will  take  fire  as  it  falls,  giving  out  fumes  of  anti- 
mony chloride  (SbCl5),  which  are  very  irritating. 

6.  Pour  a  little -boiling  water  upon  some  chips  of  logwood,  so 
as  to  obtain  a  deep  red  liquid :   add  some  of  the  solution  of  Cl,  and 
the  red  color  will  be  discharged. 

7.  Wrap  a  soda-water  bottle  in  a  towel ;  fill  it  with  water,  and 
invert  it  in  the  pneumatic  tub.     Introduce  a  glass  funnel  into  the 
neck,  and,  having  filled  a  jar  of  100  c.  c.  capacity  with  Cl,  pass  the 
gas  into  the  bottle.     Fill  the  same  jar  with  H,  and  empty  into  the 
same  bottle  ;  withdraw  the  funnel,  close  the  neck  with  the  palm  of 
the  hand,  lift  the  bottle  out  of  the  water-bath,  give  it  a  shake  to 
mix  the  gases,  and  apply  a  light.     A  sharp  explosion  will  imme- 
diately follow,  and  gaseous  HC1  be  formed.     Equal  measures  of  H 
and  Cl  unite  in  this  way,  and  the  gas  produced  occupies  the  same 
bulk  that  its  components  did  when  separate. 

*  If  this  be  large,  use  a  tin  pan  in  its  place,  and  have  a  pail  of  warm  water  for 
filling  the  bottles. 


260     DIRECTIONS    ABOUT    EXPERIMENTS. 

105. — i.  Melt  200  or  300  grams  of  NaCl  in  a  clay  crucible  at  a 
good  red  heat,  and  pour  out  the  salt  when  melted  upon  a  dry  stone 
slab.  When  cold,  break  up  the  mass  into  pieces  of  the  size  of  a 
pea,  and  preserve  them  in  a  dry  bottle.  Introduce  50  grams  of 
the  chloride  into  a  flask  provided  with  a  cork  and  bent  tube,  having 
poured  over  it  about  twice  its  weight  of  H2S04.  HC1  gas  comes 
off,  even  in  the  cold,  but  it  is  extracted  still  more  abundantly  when 
heated.  Collect  the  gas  in  dry  bottles  by  displacement.  It  may 
easily  be  ascertained  when  the  bottle  is  full,  as  a  lighted  taper  will 
be  extinguished  if  introduced. 

2.  Fill  a  flask  with  the  gas  by  displacement,  close  the  neck  with 
the  thumb,  and  immerse  it  in  a  basin  containing  infusion  of  lit- 
mus ;  on  removing  the  thumb,  the  blue  liquid  will  rush  into  the 
flask,  and  will  become  red. 

3.  Fill  a  dry  bottle  by  displacement  with  HC1  gas,  and  close  the 
mouth  with  a  glass  plate.     Withdraw  the  stopper  from  a  bottle  of 
the  same  size  containing  ammoniacal  gas  ;   invert  the  jar  of  HCl 
over  the  one  containing  the  H3N,  and  remove  the  glass  plate.    The 
two  invisible  gases  will   suddenly  combine,  a  dense  white  cloud 
will  be  formed,  and  a  solid  salt  produced. 

4.  Dilute  a  little  HCl  with  6  or  8  times  its  bulk  of  water,  and  add 
caustic  soda  cautiously,  until  the  liquid  is  neutral,  and  neither  red- 
dens blue  litmus  nor  restores  the  blue  to  red  litmus-paper.     Pour 
the  liquid  into  a  basin,  and  evaporate  it  slowly :    crystals  of  NaCl 
will  be  deposited  in  cubes. 

5.  Boil  HCl  in  a  test-tube  with  fragments  of  gold  leaf:   they  will 
not  be  dissolved.     Now  add  a  drop  or  two  of  HN03:   a  yellow 
solution  of  gold  chloride  (AuCl3)  will  be  quickly  formed. 

6.  Fill  a  test-tube  nearly  full  of  pure  rain  or  snow  water,  and 
add  a  drop  or  two  of  the  nitrate  of  silver  solution.     A  drop  of  HCl 
will  cause  a  cloudy,  white  precipitate. 

206. — i.  Grind  in  the  mortar  3  or  4  grams  of  fluor  spar,  and  mix 
with  an  equal  weight  of  powdered  glass.  Introduce  it  into  a 
Florence  flask  previously  fitted  with  a  sound  cork  and  a  tube,  as 
in  Fig.  78.  Pour  upon  the  mixture  about  30  grams  of  H2S04, 
insert  the  cork  and  tube,  and  apply  a  gentle  heat :  a  densely 
fuming  gas  is  disengaged,  consisting  of  silicic  fluoride  (SiF4). 
This  gas  must  not  be  inhaled,  as  it  is  very  irritating.  Pass  it  into 
a  glass  of  H20,  having  sufficient  Hg  at  the  bottom  to  cover  the 
mouth  of  the  delivery-tube.  Each  bubble  of  gas  as  it  rises  is 
coated  with  a  white  film  of  hydrated  silica,  while  the  water  becomes 


DIRECTIONS    ABOUT    EXPERIMENTS.     261 


The  deposit  of  silica 


Fig.  78. 


a  solution  of  hydrofluosilic  acid  (2HF,SiF4). 
would   clog  the    tube 
if  it  were  not  for  the 
H* 

107.—  i.  Fill  three 
test-tubes  nearly  full 
of  soft  water.*  Pour 
in  one  a  few  drops  of 
a  solution  of  mercuric 
chloride  ;  into  the  sec- 
ond, of  sugar  of  lead  ; 
into  the  third,  of  mer- 
cury subnitrate.  Add 
to  each  of  these  a  few 
drops  of  a  solution  of 
potassium,  iodide.  The 
first  especially  will 
produce  a  brilliant 
color,  mercury  iodide ; 
the  rapid  change  from 
yellow  to  red  is  very 
marked.  On  continuing  to  add  the  potassium  iodide,  the  red  pre- 
cipitate will  be  dissolved  and  disappear. 

2.  Make  an  additional  quantity  of  mercury  iodide.  Let  it  settle. 
Pour  off  the  liquid,  and  then  spread  the  sediment  on  a  piece  of 
heavy  card-board,  making  a  red  spot  as  large  as  a  silver  dollar. 
Dry  it  carefully.  Then  heat  very  strongly,  when  it  will  turn  yel- 
low. Rub  over  the  yellow  spot  the  point  of  a  knife  several  times, 
bearing  on  very  firmly,  until  a  red  mark  can  be  seen.  Lay  away  the 
paper  for  a  day  or  two,  and  the  red  color  will  spread  over  the 
whole  spot. 

108. — i.  Bend  the  end  of  a  piece  of  thin  platinum  wire,  8  or  10 
cm.  long,  into  a  small  hook  ;  heat  the  wire  to  redness,  and  instantly 
touch  a  crystal  of  borax  as  large  as  a  split  pea  with  the  wire :  it 
will  adhere  to  the  wire.  Then  introduce  the  wire  and  crystal  into 
the  flame  of  a  spirit-lamp.  The  borax  will  swell  up,  become 
opaque  and  white,  and  will  then  melt  into  a  clear,  glassy  bead. 

2.  Touch  the  bead  just  made  with  a  wire  moistened  with  a  solu- 


*  Melted  snow,  or  very  clear  rain-water,  will  answer  the  place  of  distilled 
water  in  making  solutions,  etc.,  for  experiments. 


262      DIRECTIONS    ABOUT    EXPERIMENTS. 

tion  of  cobalt  nitrate.  Then  melt  the  borax  again  in  the  flame.  A 
beautiful  blue  bead  is  obtained,  which  is  almost  opaque  if  the 
quantity  of  cobalt  be  considerable.  If  a  scarcely  visible  fragment 
of  manganese  oxide  be  used,  a  violet  bead  is  formed. 

3.  Dissolve  a  few  crystals  of  the  boracic  acid  in  a  small  dish  with 
a  tea-spoonful  of  alcohol.  Set  fire  to  the  spirit :  it  burns  with  a 
green  flame,  which  is  a  good  test  for  boracic  acid.  A  similar  green 
flame  is  obtained  if  a  crystal  of  borax  be  moistened  with  sulphuric 
acid  and  then  with  alcohol,  and  kindled  as  before. 

110. — i.  Grind  a  little  glass  to  a  fine  powder  in  a  mortar;  place 
it  on  a  piece  of  moistened  red  litmus-paper  ;  sufficient  alkali  will 
be  dissolved  by  the  water  to  tinge  the  paper. 

113. — i.  Melt  a  quantity  of  S,  either  the  flowers  or  brimstone,  in 
a  test-tube.  It  is  at  first  thick  and  dark-colored,  but  after  contin- 
ued heating  regains  its  fluidity.  Pour  it  now  into  water  and  it  will 
form  an  elastic  gum,  which  can  be  moulded  into  any  desired  form. 

2.  Heat  a  piece  of  brimstone  in  a  test-tube.     After  a  littlS  the  S 
will  sublime  and  collect  in  the  upper  part  of  the  tube  as  flowers  of 
sulphur. 

3.  Fill  a  cup  with  brimstone  and  melt  it  with  a  gentle  heat.     Set 
it  aside  to  cool.    When  a  crust  has  formed  on  top,  break  it  and 
pour  out  the  liquid  contents.     If  the  cup  be  broken  when  cold,  the 
bottom  will  be  found  covered  with  crystals  of  S. 

117.  ~i.  Pour  a  little  strong  sulphuric  acid  into  a  test-tube. 
Place  a  splinter  of  wood  in  it :  the  wood  will  be  blackened  in  a  few 
minutes.  Pour  i  c.  c.  of  strong  H2S04  into  a  tube  containing  3  or 
4  c.  c.  of  water :  considerable  heat  will  be  felt  to  attend  the  mix- 
ture.* Take  a  little  of  this  diluted  acid,  and  with  a  feather  dipped 
into  it  trace  a  few  letters  upon  writing-paper.  Hold  the  paper  near 
the  fire  :  the  water  will  evaporate,  leaving  the  acid  behind  ;  this  will 
soon  blacken  the  paper. 

2.  Place  in  the  evolution-flask  half  an  ounce  of  FeS.       Cover  this 
with  water,  and  then  pour  in  H.2S04  through  the  funnel  until  the 
gas  comes  off  freely.     It  may  be  passed  into  a  glass  of  cold  water. 
This  solution  must  be  bottled  and  closely  corked.     The  gas  may 
be  tested  directly,  as  mentioned  in  the  text. 

3.  Add  some  of  the  solution  to  a  dilute  one  of  antimony  tartrate  : 
a  beautiful  orange-colored,  antimony  sulphide  will  be  separated. 
With  a  dilute  solution  of  tin  chloride,  a  yellow,  tin  sulphide  will  be 

*  In  mixing  HaSO*  and  H2O  always  pour  the  acid  into  the  water. 


DIRECTIONS    ABOUT    EXPERIMENTS.     263 

formed  ;  and  with  a  solution  of  copper  sulphate,  also  largely  dilut- 
ed, a  brownish-black,  copper  sulphide  will  be  obtained. 

228. — i.  Place  a  few  drops  of  the  disulphide  in  each  of  four  test- 
tubes.  To  one  add  a  little  powdered  sulphur,  to  a  second  a  minute 
scale  of  iodine,  to  a  third  a  fragment  of  phosphorus,  and  to  a  fourth 
a  few  drops  of  water.  Notice  the  beautiful  color  produced  by  the 
iodine  :  the  solution  of  the  sulphur  and  the  phosphorus ;  and  the 
insolubility  of  the  liquid  in  water. 

120, — i.  Cover  a  stick  of  phosphorus  with  dry,  fine-powdered 
charcoal.  It  will  soon  ignite. 

2.  Put  in  a  vial  half  an  ounce  of  sulphuric  ether  and  a  half-dozen 
pieces  of  phosphorus  not  larger  than  grains  of  wheat.     Thoroughly 
shake  and  then  set  away.     Repeat  the  shaking  often.     When  the 
phosphorus  is  dissolved,  pour  a  little  of  the  solution  on  the  hands, 
and  when  briskly  rubbed  together  in  a  dark  place  they  will  glow 
with  a  ghostly  light. 

3.  Pour  some  of  the  solution  on  a  lump  of  loaf-sugar.     Drop  this 
in  hot  water,  when  the  ether  will  catch  fire. 

4.  Place  a  bit  of  phosphorus  in  a  solution  of  silver  nitrate.     In 
the  course  of  a  day  or  two  it  will  be  covered  with  brilliant  crystals 
of  reduced  silver. 

122. — i.  Dissolve  4  grams  of  caustic  potash  in  16  grams  of  water ; 
place  it  in  a  small  retort  of  about  50  c.  c.  capacity,  and  add  2  or  3 
decigrams  of  phosphorus  ;  immerse  the  beak  of  the  retort  just  below 
the  surface  of  water  in  a  small  capsule,  and  heat  the  mixture  gently. 
Bubbles  of  gas  will  form  in  the  retort,  and  will  break  with  a  flash 
and  a  slight  explosion  upon  the  surface  of  the  potash  solution.  By 
degrees  the  air  of  the  retort  will  be  deprived  of  all  its  O,  and  then 
the  bubbles  of  gas,  as  they  escape  into  the  air,  will  take  fire,  pro- 
ducing a  white  wreath  of  phosphoric  anhydride,  which  forms  a 
series  of  ringlets,  revolving  in  vertical  planes  around  the  axis  of 
the  wreath  itself  as  it  ascends.* 

124- — i.  Boil  i  gram  of  arsenious  anhydride  with  three  of  potas- 
sium carbonate  in  100  c.  c.  of  water  till  it  is  dissolved,  and  add  it 
to  a  solution  of  3  grams  of  copper  sulphate  in  100  c.  c.  of  water :  a 


*  There  is  danger  of  breaking  the  retort  by  the  bursting  of  the  bubbles  of  gas 
within  it,  before  the  air  has  all  passed  out.  A  dozen  drops  of  ether  placed  in  the 
retort  before  the  heat  is  applied  will  at  once  be  vaporized,  and  will  carry  out  the 
air.  Great  caution,  however,  is  then  necessary,  as  the  ether-vapor  is  very 
inflammable. 


$64     DIRECTIONS    ABOUT    EXPERIMENTS. 

beautiful  green  precipitate  of  Scheele's  Green  (CuHAs03)  will  be 
obtained. 

2.  Add  a  few  drops  of  a  solution  of  arsenious  anhydride  to  200 
or  300  c.  c.  of  water,  and  then  3  or  4  c.  c.  of  HCI ;  place  in  the  liquid 
two  or  three  slips  of  bright  copper  foil,  and  boil  the  whole  for  a  few 
minutes :  the  copper  foil  will  become  coated  with  a  steel-gray  film. 
Part  of  the  Cu  becomes  dissolved,  and  displaces  the  arsenic,  which 
is  thrown  down  on  the  undissolved  portion.  Pour  off  the  water, 
dry  the  Cu  on  blotting  paper,  and  heat  the  foil  in  a  tube,  sealed  at 
one  end.  The  arsenic  will  sublime,  condensing  in  minute  octahe- 
dra  on  the  cold  sides  of  the  tube.  This  is  Reinsctis  test  for  arsenic. 

127. — i.  Burn  some  dry  brushwood  ;  collect  the  ash,  wash  it  with 
five  or  six  times  its  bulk  of  water,  and  filter.  Test  the  solution 
with  a  piece  of  reddened  litmus-paper,  which  will  become  blue. 
Evaporate  the  solution  to  dryness  in  a  small  porcelain  dish.  If  the 
dry  mass  be  left  exposed  to  the  air  for  a  few  hours  it  will  become 
moist.  The  potassium  carbonate,  of  which  it  chiefly  consists, 
attracts  moisture  rapidly  and  deliquesces.  To  a  portion  of  the  salt 
add  a  few  drops  of  HC! :  brisk  effervescence  occurs. 

2.  Place  30  grams  of  pearlash  in  a  half-litre  bottle,  and  dissolve 
it  in  250  c.  c.  of  water.  Shake  20  grams  of  quicklime  with  five  or 
six  times  its  bulk  of  boiling  water,  and  add  the  pasty  mixture 
(about  120  c.  c.  in  bulk)  to  the  solution  of  pearlash.  Agitate  the 
mixture,  and  let  it  stand  till  it  is  clear.  Pour  off  a  portion  of  the 
liquid :  it  is  a  solution  of  caustic  potash.  Add  to  it  some  HCI :  no 
effervescence  will  occur.  Agitate  a  tablespoonful  of  olive  oil  in  a 
small  vial  with  3  or  4  c.  c.  of  the  caustic  solution  diluted  with  ten 
times  its  bulk  of  water :  a  milky  looking  liquid  will  be  formed, 
which  is  the  first  stage  in  the  making  of  soap. 

130. — i.  If  4  measures  of  the  cold  saturated  solution  of  potas- 
sium bichromate  be  mixed  with  5  of  oil  of  vitriol,  and  the  liquid  be 
allowed  to  cool,  chromic  anhydride  crystallizes  in  crimson  needles, 
which  may  be  drained  and  dried  upon  a  brick. 

131. — I.  The  salts  of  K  and  Na  may  also  be  distinguished  in  the 
following  manner :  To  a  pretty  strong  solution  of  the  salt  in  ques- 
tion add  a  solution  of  tartaric  acid,  and  stir  the  mixture  with  a 
glass  rod.  If  K  be  present,  white,  gritty  crystals  of  cream  of  tartar 
(KHC4H4O6)  will  be  deposited,  but  no  such  precipitate  will  occur 
with  salts  of  Na. 

137. — i.  Place  a  few  lumps  of  black  marble  in  the  open  fire,  or  in 
an  open  crucible  with  a  hole  at  the  bottom,  and  heat  it  strongly  for 


DIRECTIONS    ABOUT    EXPERIMENTS.      265 

an  hour  or  two.  When  it  is  completely  converted  into  quicklime, 
the  lumps,  when  broken  across,  will  be  quite  white. 

139. — i.  Select  a  medal  suitable  for  the  purpose  ;  paste  a  shallow 
rim  of  paper  round  it,  so  as  to  make  it  like  the  lid  of  a  pill-box,  and 
anoint  the  surface  of  the  medal  very  lightly  with  oil.  Mix  a  little 
of  the  dry  plaster  with  water  till  it  becomes  of  the  consistence  of 
thin  cream  ;  apply  it  carefully  with  a  hair  pencil  to  every  part  of 
the  surface,  so  as  to  exclude  air  bubbles  ;  then  pour  a  thicker  mix- 
ture into  the  mould.  Allow  it  to  remain  for  an  hour.  The  cast  may 
then  be  removed  :  it  will  be  a  reversed  copy  of  the  medal. 

2.  Solutions  of  calcium  salts  give  no  precipitate  with  ammonia, 
or  with  ammonia  sulphide,  but  they  give  a  white  one  of  calcium 
carbonate  with  sodium  or  potassium  carbonate,  as  do  also  the  salts 
of  barium,  and  of  strontium  ;  from  these  they  may  be  distinguished 
by  means  of  a  solution  of  calcium  sulphate,  with  which  calcium  salts 
give  no  precipitate.  Ammonia  oxalate  gives,  in  neutral  or  alkaline 
solutions  of  calcium  salts,  a  white  precipitate  of  calcium  oxalate, 
soluble  in  nitric  or  hydrochloric  acid,  but  not  in  acetic  acid.  They 
give  a  greenish  yellow  tinge  to  flame. — MILLER. 

141> — !•  Place  a  little  of  some  magnesium  salt  on  a  platinum 
wire  moistened  with  a  solution  of  cobalt  nitrate.  A  pink  residue 
will  be  obtained  on  heating  the  wire  in  the  outer  part  of  a  Bunsen 
gas-flame. 

2.  Add  to  a  solution  of  any  magnesium  salt,  such  as  the  sulphate, 
a  solution  of  potash  :  a  white  precipitate  of  hydrated  magnesia  is 
formed.  Excess  of  alkali  will  not  re-dissolve  it.  Lime-water  pro- 
duces a  similar  precipitate. 

151. — it  Allow  a  drop  of  HNO.,  to  fall  upon  a  slip  of  polished 
steel :  a  dark  grey  spot  is  produced,  owing  to  the  solution  of  the 
metal  in  the  acid,  while  the  C  is  left.  If  the  acid  be  dropped  upon 
a  slip  of  iron  a  green  stain  is  formed. 

155. — i.  Heat  a  bar  of  iron  white-hot,  and  bring  it  in  contact 
with  a  roll  of  S  over  a  pail  of  cold  water.  The  S  and  Fe  imme- 
diately unite,  and  form  drops  of  a  reddish-brown  color,  which  fall 
into  the  water.  This  is  ferrous  sulphide,  FeS,  useful  in  making  H2S 
for  laboratory  purposes. 

2.  Potassium  permanganate  (K2Mn.208)  may  be  obtained  by  mix- 
ing 40  grams  of  finely-powdered  manganese  dioxide  with  35  grams 
of  potassium  chlorate,  and  adding  a  solution  of  50  grams  of  caustic 
potash  to  the  mixture,  evaporating  to  dryness,  and  heating  the 
powdered  residue  to  dull  redness  in  a  clay  crucible.  When  cold, 
12 


2GG    DIRECTIONS    ABOUT    EXPERIMENTS. 

the  mass  is  treated  with  water,  and  decanted  from  the  insoluble 
residue  ;  a  splendid  purple  liquid  is  obtained,  which  on  evaporation 
yields  needles  of  the  permanganate. 

2S8. — i.  Fill  a  test-tube  nearly  full  of  H2O.  Pour  in  it  a  few 
drops  of  the  solution  of  copper  sulphate.  Add  H3N,  and  a  blue 
precipitate  will  be  formed.  Notice  the  change  from  green  to  blue. 
The  copper  sulphate  may  be  readily  prepared  for  this  experiment 
by  covering  a  copper  cent  with  dilute  oil  of  vitriol.  This  experi- 
ment may  be  made  to  show  the  divisibility  of  matter  by  weighing 
the  cent,  finding  what  proportion  of  the  whole  solution  you  use,  and 
then  experiment  to  see  what  quantity  of  water  can  be  taken  and 
yet  have  the  blue  color  perceptible  in  the  ammonia  test. 

2.  Beside  the  ammonia  test  for  copper,  the  metal  may  be  detected, 
i,  by  the  red  metallic  deposit  formed  on  a  polished  plate  of  iron  if 
dipped  into  a  solution  of  the  salt  ;  2,  by  the  black  insoluble  sul- 
phide produced  by  H2S  ;  and  3,  by  the  blue  hydrate  turning  black 
on- heating. 

160. — i.  If  a  water  contain  lead,  even  in  minute  quantity,  its 
presence  is  easily  ascertained  by  taking  two  similar  jars,  25  c.  m. 
high,  of  colorless  glass,  filling  both  of  them  with  the  water,  and 
adding  to  one  of  the  jars  3  or  4  c.  c.  of  a  solution  of  sulphuretted 
hydrogen.  A  quantity  of  lead  less  than  one  part  in  two  millions  is 
easily  perceived,  by  the  brown  tinge  occasioned,  on  looking  down 
upon  a  sheet  of  white  paper  ;  the  jar  to  which  the  test  has  not  been 
added  serving  as  a  standard  of  comparison. 

162. — i.  Place  a  little  gold  leaf  in  two  test-tubes  ;  to  one  add 
HNO3,  to  the  other  HC1.  Even  when  heated,  the  gold  leaf  will 
remain  unaffected  in  each.  Pour  the  contents  of  one  tube  into  the 
other  :  the  Au  will  disappear  with  effervescence.  Evaporate  this 
solution  in  a  small  porcelain  dish  till  the  acid  is  nearly  all  driven 
off:  gold  chloride  will  be  left. 

2.  Dilute  the  solution  with  3  or  4  c.  c.  of  H20.  To  a  portion  of 
this  liquid  add  a  solution  of  ferrous  sulphate  :  a  brown  precipitate 
of  finely  divided  reduced  Au  is  obtained,  and  iron  chloride  is 
formed. 

167. — i.  Dissolve  a  ten-cent-piece  in  HNO;J.  The  solution  has  a 
bluish  color,  owing  to  the  presence  of  the  Cu.  Dilute  with  200  c.  c. 
of  water  ;  then  add  a  solution  of  NaCl  so  long  as  it  forms  a  precip- 
itate :  white  flakes  of  silver  chloride  are  formed.  Stir  the  mixture 
briskly  with  a  glass  rod :  the  precipitate  will  collect  into  clots. 
Filter  the  solution.  The  presence  of  Cu  may  be  found  in  the  clear 


DIRECTIONS    ABOUT    EXPERIMENTS.    267 

liquor  by  adding  H3N  in  excess  to  a  portion  of  the  liquid  :  a  blue 
solution  is  formed.  Place  the  blade  of  a  knife  in  another  portion 
of  the  filtrate :  it  will  become  coated  with  metallic  Cu. 

2.  Take  the  precipitated  silver  chloride,  and  after  having  washed 
it  well  on  a  filter,  place  it  in  a  wine-glass  with  a  little  water ;  add 
two  or  three  drops  of  H2S04,  and  then  place  a  slip  of  Zn  in  contact 
with  the  chloride,  and  leave  it  for  twenty-four  hours.     The  chloride 
will  be  reduced  to  metallic  Ag,  which  will  have  a  grey,  porous 
aspect,  while  zinc  chloride  will  be  found  in  solution.     Lift  out  the 
piece  of  Zn  carefully  ;  wash  the  Ag  first  with  water  containing  a  lit- 
tle H2 SO 4,  then  with  pure  H20.     Dry  the  residue.     Place  a  small 
quantity  of  it  upon  an  anvil,  and  strike  it  a  blow  with  a  hammer : 
a  bright  metallic  surface  will  be  produced.     Place  a  little  of  the 
grey  powder  upon  charcoal,  and  heat  in  the  flame  of  the  blow-pipe  : 
it  will  melt  into  a  brilliant  malleable  bead.     Dissolve  another  por- 
tion in  HNO3  ;  red  fumes  will  escape,  and  silver  nitrate  be  obtained 
in  solution. 

3.  Fill  a  vial  half-full  of  a  solution  of  silver  nitrate  and  add  a 
few  globules  of  Hg.     The  Ag  will  be  precipitated  in  a  few  days, 
forming  the  "  silver  tree." 

192. — i.  To  one  gill  of  water  add  fifteen  or  twenty  grains  of  strong 
H2S04.  Place  in  a  large  flask  and  heat.  While  boiling,  drop  in 
slowly  two  drams  of  starch,  finely  powdered.  Boil  for  several 
hours,  adding  water  as  may  be  necessary.  Finally,  drop  in  slowly 
fine  chalk  until  the  liquid  is  neutral ;  then,  cool,  filter  off  the  cal- 
cium sulphate,  and  evaporate  the  liquid  to  a  syrup. 

219. — i.  Fill  a  test-tube  one-sixth  full  of  sweet  oil,  add  a  little 
ammonia,  and  nearly  fill  with  water.  The  constituents  remain  sep- 
arate. Shake  thoroughly,  and  they  will  combine,  forming  a  thin, 
soapy  liquid.  Add  an  acid,  and  they  will  separate  at  once. 

EQUIVALENTS     OF    THE     METRIC    WEIGHTS    AND     MEASURES 
USED    IN    THESE    EXPERIMENTS. 

i  decigram  =  about    1.5  grains, 

i  gram  =      "      15.5      " 

i  litre  =      "        2.1  pints. 

I  cubic  centimetre  (c.c.)  =      "      15.5  grains. 
I  millimetre  (m.m.)  =      "          .04  inch. 

I  centimetre  (c.m.)  =      "          .4       " 


QUALITATIVE    ANALYSIS, 

FOR     BEGINNERS. 


[The  following  pages  on  analysis  were  prepared  by  EDWARD  J.  HALLOCK, 
A.M.,  of  Columbia  College,  N.  Y.] 

IN  order  to  be  able  to  analyze  almost  every  inorganic  substance 
met  with  in  the  arts,  or  sold  in  the  shops,  it  is  only  necessary  for 
the  student  to  familiarize  himself  with  the  reactions  of  about  twenty- 
six  metals  and  a  dozen  acids.  To  be  able  to  apply  these  tests  with 
certainty,  in  all  cases,  and  to  know  the  easiest  and  best  methods  of 
dissolving  the  substance,  constitute  a  qualitative  chemist. 

For  reasons  which  will  appear  farther  on,  metals  are  divided  into 
five  groups. 

THE  FIRST  GROUP  embraces  lead,  silver,  and  the  suboxide  salts 
of  mercury.  They  are  classed  together  because  they  are  the  only 
metals  whose  chlorides  are  insoluble  in  acids.  The  student  should 
take  a  solution  of  lead  nitrate  Pb  (NO;J)2,  formed  by  dissolving  lith- 
arge in  nitric  acid,  or  some  lead  acetate  solution  (see  page  161),  and 
try  the  following  tests,  making  a  note  of  his  results.  With  HC1  a 
white  precipitate  of  PbCl2  is  formed.  This  precipitate  is  filtered 
out,  washed,  and  dissolved  in  boiling  water.  To  another  portion 
of  the  solution  add  H2S04,  a  white  precipitate  of  PbS04,  insoluble 
in  H2O.  To  a  third  portion  add  potassium  bichromate,  K2Cr207 
(page  130) ;  a  yellow  precipitate  is  formed. 

Repeat  each  of  these  tests  with  silver  nitrate,  AgNO;J  (Experiment 
167).*  The  precipitate  with  HC1  is  insoluble  in  boiling  H2O,  but 
dissolves  in  NH4HO.  Repeat  with  mercurous  nitrate,  HgNOs,  made 
by  the  action  of  cold  HN03  on  an  excess  of  Hg. 

*  These  numbers  refer  to  the  Experiments  in  the  Appendix. 


QUALITATIVE    ANALYSIS. 

We  have  with  HC1  a  precipitate  of  calomel  (HgCl),  (page  172),  which 
is  insoluble  in  H20,  and  blackens  on  adding  NH4HO,  but  does  not 
dissolve. 

SEPARATING  METALS  OF  GROUP  I. — Mix  the  solutions  of  the  three 
metals,  and  add  HC1.  Filter,  and  boil  the  precipitate  in  water; 
filter  hot,  and  to  the  filtrate  add  K2Cr2O7.  The  yellow  precipitate 
proves  that  lead  is  present.  Boil  the  residue  in  ammonia  and 
filter;  to  the  filtrate  add  HN03.  A  white  precipitate  proves  silver 
present.  The  black  insoluble  residue  is  a  compound  of  mercury 
(Hg2H2NCl). 

THE  SECOND  GROUP  .embraces  the  protoxide  salts  of  mercury, 
together  with  Pb,  Bi,  Cu,  Cd,  As,  Sb,  Sn,  Au,  and  Pt.  They  are  pre- 
cipitated from  acid  solutions,  by  H2S  gas  being  passed  through  the 
solution,  as  sulphides.  (See  Experiment  117.)  Of  these  HgS,  PbS, 
Bi2S3,  CuS,  and  CdS  are  insoluble  in  ammonium  sulphide  (NH4)2S, 
and  constitute  the  first  division  of  this  group.  The  sulphides  of  the 
remaining  five  metals  are  soluble  in  (NH4)2S,  and  form  the  second 
division.  (NH4)2S  is  prepared,  according  to  Fresenius,  by  saturat- 
ing a  given  volume  of  ammonia  solution  (specific  gravity  0.96)  with 
H2S  gas,  and  adding  to  it  an  equal  volume  of  the  ammonia.  The 
solution,  which  is  at  first  colorless,  soon  becomes  yellow  by  keep- 
ing, or  may  be  at  once  converted  into  the  yellow  sulphide  by  the 
addition  of  sulphur.  It  should  yield  no  precipitate  with  magnesium 
sulphate  (Epsom  salt).  This  reagent  is  decomposed  by  acid,  sul- 
phur being  precipitated. 

Pass  H2S  gas  into  a  solution  of  corrosive  sublimate  (HgCl2) ;  a 
precipitate  is  formed  which  is  at  first  white,  then  yellow,  red,  and 
finally  black.  It  is  insoluble  in  (NH4)2S,  and  in  HNO:J.  When  dis- 
solved in  aqua  regia  it  gives  a  grey  precipitate  with  SnCl2.  Repeat 
the  first  experiment  with  some  lead  solution  ;  a  black  precipitate  is 
formed,  soluble  in  boiling  HNO;}.  In  this  solution  a  white  precipi- 
tate of  PbS04  is  formed  on  adding  H2S04.  Add  a  few  drops  of  KI 
solution  to  the  original  solutions  of  HgCl2,  and  Pb(NO:3)2  ;  in  the  for- 
mer case  the  precipitate  (HgI2)  is  red,  in  the  latter  (PbI2 )  it  is  yellow. 
These  tests  are  characteristic  of  the  metals  when  alone.  (Experi- 
ment 107.)  Pass  H2S  into  Bi(N03)3  solution  ;*  a  black  precipitate  ; 
dissolve  in  HNO:J  ;  add  a  drop  of  H2S04  to  prove  it  is  not  lead  ;  then 
cautiously  add  ammonia,  which  produces  a  white  precipitate  of 

*  When  Bi  solutions  are  diluted  with  water,  basic  salts  are  precipitated  unless 
there  be  too  much  free  acid  present.  This  reaction  is  most  sensitive  with  BiCl3, 
so  that  HC1  may  be  used  to  dissolve  the  Bi(NO3)3  for  the  HaO  test. 


270  QUALITATIVE    ANALYSIS. 

Bi(HO)3.  Repeat  all  the  above  experiments  with  CdS04  solution; 
the  precipitate  with  H2S  is  a  beautiful  yellow,  soluble  in  HN03,  but 
insoluble  in  KCy.  Pass  H2S  in  CuS04  solution,  and  a  brownish- 
black  precipitate  will  be  formed,  soluble  in  HNG3  and  in  KCy. 
Salts  of  copper  have  a  bluish  color,  which  becomes  more  intense  on 
adding  NH4HO.  (Experiment  158.)  With  potassium  ferrocyanide 
(K4FeCy6)  they  give  a  reddish-brown  precipitate  insoluble  in  HC1. 

SEPARATING  METALS  OF  SECOND  GROUP,  FIRST  DIVISION. — After 
the  student  has  made  all  the  above  reactions  he  may  mix  the  solu- 
tions of  the  five  metals  and  proceed  to  separate  them.  Most  of  the 
lead  is  precipitated  by  HC1,  and  is  filtered  out  before  H2S  is  passed 
through  the  solution.  The  precipitate  with  H2S  is  boiled  in  HNO3, 
and  HgS  remains  as  a  residue.  When  the  solution  is  very  acid,  part 
of  the  H2S  is  decomposed  and  S  precipitated,  which  must  not  be 
mistaken  for  HgS.  To  the  filtrate  add  a  little  H2S04  to  precipitate 
any  lead  present;  filter  and  add  NH4HO,  when  Bi(HO);J  is  precipi- 
tated. The  precipitate,  dissolved  in  aqua  regia  and  concentrated  by 
evaporation,  should  give  a  white  precipitate  if  poured  into  water. 
The  addition  of  NH4C1  aids  this  reaction.  The  blue  filtrate  from  the 
Bi  precipitate  is  boiled  with  KCy,  care  being  taken  not  to  inhale  the 
fumes,  and  H2S  added  ;  CdS  forms  a  yellow  precipitate.  The  pres- 
ence of  Cu  in  the  filtrate  is  proved  by  the  formation  of  a  reddish- 
brown  precipitate  with  HNO3  and  K4FeCy6. 

The  most  interesting  metal  of  group  second,  second  division,  is 
As.  The  sulphide  is  a  beautiful  yellow  resembling  Cd,  but  unlike 
Cd  it  is  soluble  in  (NH4)2S,  and  in  (NH4)2C03.  The  salts  of arsen- 
ious  acid  yield  with  AgN03,  yellow  precipitates,  Ag3As03  soluble  in 
HN03.  A  small  piece  of  bright  green  wall-paper  usually  contains 
enough  of  this  metal  to  give  several  characteristic  tests.  Apply  a 
single  drop  of  nitric  acid  to  the  paper ;  a  moment  after  neutralize 
with  ammonia  and  observe  the  color,  a  deep  blue  always  indicating 
copper.  When  the  white  fumes  have  nearly  disappeared,  apply  to 
the  same  spot  a  drop  of  AgN03  ;  a  yellow  ring  indicates  As.  The 
most  delicate  test  for  As  as  well  as  Sb  is  Marsh's  test  (see  page  124); 
The  mirror  formed  by  As  on  porcelain  is  soluble  in  bleaching  pow- 
ders (see  page  106),  sodium  hypochlorite,  also  called  Labarraque's 
solution  (see  note,  page  104),  etc. ;  that  of  Sb  is  insoluble  in  these 
(see  note,  page  173).  If  AsH3  is  passed  into  AgN03,  metallic  Ag  is 
precipitated  and  enough  HN03  is  set  free  to  keep  the  yellow  Ag;JAsO3 
in  solution  until  it  is  boiled  with  sodium  acetate,  when  the  precipi- 
tate reappears. 


QUALITATIVE     ANALYSIS.  271 

Antimony  closely  resembles  As  in  its  reactions.  Pass  H2S  into 
a  solution  of  tartar  emetic  (Experiment  117,  3),  and  an  orange-colored 
precipitate  will  be  formed,  soluble  in  (NH4)2S,  but  nearly  insoluble 
in  dilute  (NH4)3C03.  Put  some  of  the  first  solution  in  a  new  Marsh's 
apparatus.  The  mirror  formed  is  insoluble  in  bleaching  powders, 
or  sodium  hypochlorite.  If  both  As  and  Sb  are  suspected  in  the  same 
solution,  the  gases  AsH3  and  SbH3,  formed  by  introducing  the  solu- 
tion into  a  hydrogen  generator,  are  passed  into  AgN03.  The  Sb 
forms  SbAga,  which  is  precipitated  with  the  metallic  Ag,  while  the  As 
remains  in  solution.  The  precipitate  is  filtered  out,  boiled  in  tar- 
taric  acid,  filtered,  and  H2S  added  to  filtrate,  when  an  orange-red 
precipitate  proves  the  presence  of  Sb.  To  prove  the  presence  of  As, 
the  filtrate  from  the  Ag  and  SbAg:J  is  boiled  with  sodium  acetate  to 
precipitate  the  yellow  Ag;iAs03  as  above  mentioned. 

Gold  and  platinum  are  distinguished  from  all  other  metals  by 
their  insolubility  in  HC1  or  HN03,  but  are  converted  into  soluble 
chlorides  by  aqua  regia.  The  characteristic  test  for  Au  salts  is  SnCl2 
mixed  with  SnCl4,  the  purple  of  Cassius  being  formed.  FeS04  pre- 
cipitates metallic  Au  as  a  fine  powder.  (Experiment  162,  2.)  PtCl4 
is  precipitated  by  KC1  as  yellow  K2PtCl6.  Pt  and  Au  give  black  pre- 
cipitates with  H2S.  Tin  is  soluble  in  HC1,  but  is  oxidized  by  HN03 
without  dissolving.  There  are  two  series  of  tin  salts  ;  SnCl2  gives 
a  black  precipitate  with  H2S  ;  SnCl4  a  yellow  precipitate  with  H2S, 
both  soluble  in  yellow  (NH4)2S.  AuCl3  is  a  test  for  Sn.  SnCl2  forms 
with  an  excess  of  HgCl2,  a  white  precipitate  of  HgCl ;  but  when 
SnCl2  is  in  excess  a  gray  precipitate  of  Hg  is  formed. 

SEPARATING  METALS  OF  SECOND  GROUP,  SECOND  DIVISION. — 
Into  an  acid  solution  of  Au,  Pt,  Sn,  Sb,  and  As,  pass  H2S  gas ;  filter 
and  dissolve  precipitate  in  (NH4)2S  to  remove  any  members  of  first 
division  present.  Precipitate  the  sulphides  by  HC1,  and  place  in  a 
hydrogen  generator.  The  As  and  Sb  combine  with  H,  and  are  sep- 
arated as  above  by  passing  the  AsH3  and  SbH3  into  AgN03.  The 
metallic  Sn,  Au,  and  Pt  remain  in  the  H  generator ;  the  Sn  is  then 
dissolved  out  with  HC1,  and  tested  with  HgCU  ;  the  Au  and  Pt  are 
dissolved  in  aqua  regia  and  tested  in  separate  portions  of  the  solu- 
tion as  above  described. 

GROUP  THIRD  embraces  Co,  Ni,  Fe,  Cr,  Mn,  U,  Al,  and  Zn.  They 
are  precipitated  by  (NH4)2S  from  neutral  or  alkaline  solutions. 
The  characteristic  test  for  Co,  is  the  blue  color  imparted  to  a  borax 
bead.  (Experiment  108.)  Ni  alone  gives,  in  the  outer  blow-pipe 
flame,  a  reddish-brown  bead.  Both  give  with  (NH4)3S  black  preci- 


272  QUALITATIVE    ANALYSIS. 

pitates  insoluble  in  dilute  HC1.  If  KN02  and  acetic  acid  are  added 
to  a  solution  of  Co  and  Ni,  the  former  is  slowly  precipitated  and 
not  the  latter.  To  a  solution  of  FeSO4,  add  a  drop  of  potassium 
ferricyanide  (K6Fe2Cy]2);  a  blue  precipitate  is  formed.  To  an- 
other portion  add  (NH4)2S  ;  a  black  precipitate  is  formed,  soluble  in 
dilute  HC1,  from  which  solution  it  is  re-precipitated  by  NaHO,  as 
Fe(HO)2.  Repeat  the  latter  test  with  ferric  chloride  (Fe2Cl6)  and 
the  same  result  is  obtained.  Fe2Cl6  gives  with  K4FeCy6  a  precipi- 
tate of  Prussian  blue.  Into  a  glass  of  water  place  one  drop  of 
Fe2Cl6,  and  add  potassium  sulphocyanide  (KCyS) ;  the  liquid  acquires 
a  beautiful  red  color.  Iron  salts  also  give  characteristic  colors  to 
the  borax  beads.  To  a  solution  of  MgSO4,  add  (NH4)2S  ;  a  flesh- 
colored  precipitate  is  formed,  soluble  in  HC1,  re-pnecipitated  on 
boiling  in  NaHO,  as  Mn(HO)2.  The  borax  bead  with  Mn  acquires 
an  amethyst-red  color  (see  note,  page  109)  in  the  outer  blow-pipe 
flame.  Fused  with  Na2C03  and  KNO3  a  green  mass  is  formed. 
(NH4)2S  gives  with  compounds  of  Cr,  a  greenish  precipitate  of 
Cr2(HO)6,  soluble  in  HC1,  and  re-precipitated  by  NaHO.  Fused  with 
NaaC03  and  KNO3  it  forms  a  yellow  mass.  With  Pb(NO:,)2  it  gives 
a  yellow  precipitate.  Uranium  gives  with  (NH4)2S  a  black  precipi- 
tate, soluble  in  HC1,  re-precipitated  by  NaHO,  which  precipitate  is 
soluble  in(NH4)2CO:1.  With  K4FeCy6  it  yields  a  red  precipitate. 
(NH4)2S  produces  in  solutions  of  Al  salts  a  white  precipitate,  solu- 
ble in  HC1,  from  which  it  is  re-precipitated  by  NH4C1,  but  not  by 
NaHO.  Zn  salts  are  also  precipitated  white  by  (NH4)2S  ;  the  pre- 
cipitate is  soluble  in  HC1  and  not  re-precipitated  by  NaHO.  After 
the  student  has  carefully  repeated  all  the  tests  above  given,  he  is 
prepared  to  undertake  the 

SEPARATION  OF  METALS  OF  GROUP  THIRD. — Some  NH4C1  and 
NH4 HO  is  first  added  (see  page  274),  then  (NH4)2S.  The  precipi- 
tate is  digested  in  dilute  HC1  ;  Ni  and  Co  are  sought  in  the  residue. 
The  filtrate  is  boiled  with  NaHO  for  half  an  hour  in  a  porcelain 
capsule,  and  filtered.  The  filtrate  is  divided  in  two  portions,  to 
one  of  which  NH4C1  is  added  to  precipitate  Al,  to  the  other  H2S  to 
precipitate  the  Zn.  The  residue  is  boiled  in  (NH4)-,CO;J  to  dis- 
solve U,  which  is  tested  with  K4FeCy6.  The  residue,  containing  Fe, 
Mn,  and  Cr,  is  fused  with  pure  KNO;,  and  Na2CO:5  ;  if  the  mass  is 
green,  Mn  is  indicated  ;  if  yellow,  Cr.  One-half  of  the  mass  is  dis- 
solved in  water ;  the  insoluble  residue  is  tested  for  iron  ;  the 
filtrate  is  tested  for  Cr  by  first  neutralizing  with  acetic  acid,  and  then 
adding  Pb(N03)2.  The  test  for  Mn  is  to  place  some  of  the  fused 


QUALITATIVE    ANALYSIS.  213 

mass  in  HN03  with  red  lead  ;  if  left  at  rest,  a  beautiful  rose  pink 
is  formed  from  the  reduction  of  K2Mn04  to  K2Mn208.  (Experiment 
155,  2.) 

GROUP  FOURTH  embraces  the  metals  of  the  alkaline  earths,  Ba, 
Sr,  and  Ca,  whose  carbonates,  precipitated  by  (NH4)2C03  are  in- 
soluble in  H2O,  but  soluble  in  HC1.  BaCl2  forms  with  H2S04  a 
precipitate  insoluble  in  acids ;  it  is  also  precipitated  by  hydrofluo- 
silicic  acid  (2HF,SiF4),  (Experiment  106),  more  easily  in  presence  of 
alcohol.  Ba  compounds  impart  a  green  color  to  the  flame  of  an 
alcohol  lamp  or  Bunsen  burner.  CaCl2  with  ammonium  oxalate, 
yields  a  white  precipitate  insoluble  in  water.  H2S04  produces  a 
white  precipitate  of  CaS04,  slightly  soluble  in  water  and  acids.  Ca 
salts  color  the  flame  yellowish-red.  SrCl2  gives  a  white  precipi- 
tate with  a  clear  solution  of  CaSO4  ;  if  the  solution  is  dilute,  half 
an  hour  is  required  for  the  precipitation.  Sr  colors  the  flame  car- 
mine-red. 

SEPARATING  METALS  OF  GROUP  FOURTH. — Some  NH4C1  is  first 
added,  if  not  already  present  in  the  solution,  then  (NH4)2C03.  The 
precipitate  is  dissolved  in  HC1,  then  alcohol  and  2HF,SiF4  are  added 
until  all  the  Ba  is  thrown  down.  The  solution  is  then  divided,  and 
to  one  portion  NH4HOand  CaS04  is  added;  SrS04  separates  in 
half  an  hour.  To  the  other  portion  H2S04  is  added,  and  a 
precipitate  of  SrS04  and  CaSO4  filtered  out ;  the  filtrate  is  then 
tested  for  Ca  with  ammonium  oxalate. 

When  phosphoric  acid  is  present,  Ca,  Ba,  and  Sr  are  precipitated 
in  Group  IV,  and  the  following  method  is  then  preferred  to  the 
one  above  given  for  separating  the  members  of  that  group.  The 
filtrate  from  Group  II  is  boiled  to  expel  H2S,  then  NH4C1  and 
NH4HO  are  added,  which  precipitate  Ba,  Sr,  Ca,  Al,  Mg,  Fe,  Mn,  Cr, 
and  H3PO4,  while  Co,  Ni,  Zn,  and  some  Mn  remain  in  solution  and 
are  to  be  precipitated  as  usual  with  (NH4)2S.  The  NH4HO  pre- 
cipitate is  boiled  with  oxalic  acid  until  it  becomes  white  and 
pulverulent,  which  converts  Ca,  Ba,  and  Sr  into  oxalates.  When 
cold,  sodium  acetate  is  added,  which  dissolves  all  except  the  Ca,  Ba, 
and  Sr,  which  are  tested  for  in  the  residue.  The  filtrate-  is  boiled 
with  NaHO,  which  precipitates  Mg,  Fe,  Mn,  and  Cr.  The  filtrate 
contains  Al  and  H3PO4,  which  are  separated  by  HC1  and  NH4HO, 
the  Al  being  precipitated,  and  H3P04  found  in  the  filtrate.  The 
precipitate  with  NaHO  is  treated  with  NH4C1,  which  dissolves  out 
the  Mg,  leaving  Fe,  Mn,  and  Cr  to  be  fluxed  with  Na2C03  and 
KNO3  as  before.  (See  page  272.) 


QUALITATIVE    ANALYSIS. 


GROUP  FIFTH  embraces  Mg,  K,  Na,  and  L.  As  lithia  is  very 
rare,  we  omit  its  reactions.  MgS04  yields  a  white  precipitate  of 
Mg(HO)2  on  the  addition  of  NH4HO,  unless  the  solution  contains 
NH4C1  ;  hence  the  necessity  of  adding  NH4C1,  before  testing  for 
Groups  III  and  IV,  where  NH4 HO  would  otherwise  throw  down 
Mg.  The  salts  of  Mg  give  a  white  precipitate  with  hydrodisodic 
phosphate,  Na2HP04  and  NH4HO.  KC1  yields  a  yellow  precipi- 
tate with  PtCl4.  Potassium  acetate  is  also  precipitated  in  concen- 
trated solutions  by  tartaric  acid.  K2S04  gives  a  white  precipitate 
with  2HF,SiF4  and  alcohol.  K  imparts  a  violet  color  to  flame,  which 
appears  red  when  viewed  through  blue  glass.  Na  is  not  precipi- 
tated by  any  of  the  above  reagents  ;  but  may  give  with  NaSb03  a 
white  precipitate.  It  imparts  an  intense  yellow  color  to  flame.  K, 
Na,  and  L,  as  well  as  Ca,  Ba,  and  Sr  are  easily  detected  by  the 
spectroscope. 

Ammonia  is  liberated  from  its  compounds  by  mixing  with  NaHO 
or  Ca(HO)2,  and  is  then  recognized  by  the  smell,  by  bluing  red 
litmus,  and  by  producing  white  fumes  when  a  rod  moistened  with 
HC1  is  held  over  it.  (See  pages  49,  135.) 

SCHEME  FOR  THE  SEPARATION  OF  THE  METALS  IN  GROUPS  III 

AND    IV   WHEN    H3P04    IS   PRESENT. 


SOL. 


Add  NH«C1  +  NH4HO  to  the  filtrate  from  Group  II. 
PREC. 


Ca,  Ba,  Sr,  Al,  Mg,  Fe,  Mn,  Cr,  H3POt 
Boil  with  CaH3O4,  and  when  cold  add  NaCaH3Oa. 
RES.  SOLUTION. 


Al,  Mg,  Fe,  Mn,  Cr,  H3PO4. 

Boil  in  NaHO  for  10  min. 
SOL.  PREC. 


A12O3,  H3PO4 
HC1  +  NH.HO. 
PREC.  SOL. 


Al. 


H3PO4. 

Test  with  MgSO< 


SOL. 


Mg,  Fe,  Mn,  Cr. 
NH4C1. 
RES. 


Mg. 

2-3 
"8 


Fe,  Mn,  Cr. 
Fuse  with  NaaCOs  and 

KNO3. 
Test  as  usual. 


QUALITATIVE    ANALYSIS.  275 


TESTS      FOR      ACIDS. 

The  acids  do  not  admit  of  the  strict  grouping  and  successive 
separation  employed  for  metals,  and  we  will  rest  content  with  men- 
tioning  the  simplest  tests  for  the  principal  acids,  beginning  with 
the  haloids : 

HC1  with  AgN03,  white  precipitate,  soluble  in  NH4HO. 

HI       "        "        yellowish  precipitate,  insoluble  in  NH4HO. 

HI      "      HgCl2,  red  precipitate,  soluble  in  KI. 

HI  '*  starch  paste  and  Cl  solution  or  bleaching  powders,  blue 
color.  (See  page  107.) 

CaF2  with  H2S04  liberates  HF,  which  attacks  glass.    (See  p.  106.) 

HBr      "     starch  paste  and  Cl  water,  an  orange-yellow  color. 

H2S04  with  BaCl2,  white  precipitate,  insoluble  in  HC1. 

Si02  is  insoluble  in  H20,  as  are  most  of  the  silicates  except 
those  of  K  and  Na.  In  analyzing  the  soluble  silicates,  they  are 
first  evaporated  to  dryness  with  excess  of  HC1,  the  soluble  chlorides 
dissolved  in  H20  or  HC1,  and  the  Si02  left  as  a  griity  powder. 

Boracic  Acid  is  detected  by  placing  it  in  a  capsule  containing 
alcohol  and  H2S04,  and  igniting  the  alcohol.  A  green  tinge  to 
the  flame  indicates  Bo.  (See  page  109.)  If  a  solution  of  an  alka- 
line borate  is  mixed  with  HC1  until  slightly  acid,  a  slip  of  turmeric 
paper  dipped  in  it  and  dried  at  212°,  acquires  a  peculiar  red 
tint. 

H3P04  with  AgNO:?,  yellow  precipitate,  soluble  in  HN03. 

"          "     solution  of  ammonium  molybdate  in  HNO3,  fine  yel- 
low precipitate. 

H3PO4  with  MgSOj,  solution  containing  NH4C1  and  NH4HO,  a 
white  precipitate  soluble  in  acids.  (See  test  for  Mg,  page  274.) 

C02.  Carbonates  effervesce  on  the  addition  of  acids,  C02  being 
set  free,  which  extinguishes  a  match  inserted  in  the  test  tube. 
The  ear  is  often  able  to  detect  slight  effervescence  not  otherwise 
perceptible.  (See  page  74.) 

HNO:,  is  not  precipitated  by  any  reagent.  Into  a  test-tube  con- 
taining some  nitrate,  drop  a  crystal  of  FeS04,  then  allow  a  drop  of 
H2S04  to  flow  down  the  side  of  the  test-tube  which  is  held  in- 
clined. A  dark-brown  ring  of  sesquioxide  forms  immediately. 
If  Cu  and  strong  H2S04  are  heated  with  a  nitrate,  red  fumes  are 
given  off.  A  nitrate  heated  on  charcoal  deflagrates. 


276  QUALITATIVE    ANALYSIS. 

Chlorates  deflagrate  more  violently  than  nitrates.  H2S04  liber- 
ates C102  which  is  betrayed  by  its  color  and  odor.  If  a  crystal  of 
KC103  and  a  piece  of  P  be  placed  in  a  glass  of  water,  and  a  drop 
of  H2S04  conveyed  to  it  by  a  pipette  or  tube,  the  P  takes  fire 
and  burns  under  water  (page  130,  Experiment  2).  All  experiments 
with  chlorates  must  be  performed  with  minute  quantities,  because 
of  the  great  danger  of  explosions. 

S02  is  easily  recognized  by  its  odor.  When  sulphites  are  treated 
with  HC1,  the  S02  is  evolved. 

If  Cl  gas  be  given  off  on  heating  a  substance  in  HC1,  the  pres- 
ence of  a  binoxide  may  be  suspected.  (See  page  103.) 

HCy  with  AgN03,  white  precipitate  soluble  in  KCy  ;  difficultly  solu- 
ble in  NH4HO.  If  FeS04  and  a  little  Fe2Cl6  are  added  to  a  solution 
of  a  cyanide  acidified  with  HC1  no  change  takes  place,  but  on  add- 
ing  KHO  a  bluish-green  precipitate  is  formed.  Care  must  be  taken 
in  handling  the  poisonous  cyanides.  On  adding  HC1  to  a  cyanide, 
HCy  is  liberated,  and  is  detected  by  the  odor,  which  resembles  bitter 
almonds. 

H4FeCy6  with  AgN03,  white  precipitate  insoluble  in  NH4HO,  and 
in  HN03.  With  Fe2Cl,j,  or  any  other  ferric  salt,  Prussian  blue 
[Fe4(FeCy6)3]  is  formed.  Insoluble  ferrocyanides  are  decomposed 
on  boiling  with  KHO,  forming  K4FeCy6  ;  and  the  metallic  oxide,  if 
insoluble  in  KHO,  is  precipitated. 

H6Fe2Cy12  with  AgN03,  orange-colored  precipitate  soluble  in 
NH4HO  and  KCy.  With  FeS04,  or  any  other  ferrous  salt,  a  blue 
precipitate  is  formed.  KHO  decomposes  insoluble  ferricyanides. 

Oxalic  Acid,  H2C2O4,  yields  a  white  precipitate  with  CaCl2,  which 
is  insoluble  in  NH4C1. 

Citric  Acid,  H3C6H507,  also  yields  a  white  precipitate  with  CaCL, 
but  unlike  the  above  it  is  soluble  in  NH4C1,  and  insoluble  in  KHO. 
On  boiling  the  solution  in  NH4C1,  an  insoluble  citrate  of  lime 
separates. 

Tartaric  Acid,  H2C4H406,  is  precipitated  by  CaCl2  in  excess. 
The  precipitate  is  soluble  in  cold  KHO,  and  is  re-precipitated  on 
boiling,  and  redissolved  on  cooling.  KC2H30.2  (formed  by  adding 
acetic  acid  to  K2C03  and  filtering)  precipitates  tartaric  acid,  if  both 
solutions  are  strong.  Pb(C2H302)2  also  produces  a  precipitate. 

Acetic  Acid,  C2H4O2,  is  usually  detected  by  the  odor  given  off  on 
heating  it  with  equal  volumes  of  H2S04  and  pure  alcohol.  If 
FeeCl6  is  added  to  a  hot  solution  of  an  acetate,  a  dark-red  color  is 
produced. 


QUALITATIVE     ANALYSIS.  877 


PRELIMINARY     TESTS. 

A  few  tests  in  the  dry  way  will  give  some  clew  to  the  substances 
present ;  but  in  a  complete  analysis  every  acid  and  every  metal  must 
be  sought  for. 

I.  HEATING  IN  A  TUBE  OF  HARD  GLASS  CLOSED  AT  ONE  END. — 
If  the  substance  blackens,  organic  matter  is  present.     If  vapors 
escape,  they  are  tested  for  C02,  S02,  H2S,  etc.     If  a  sublimate  is 
formed,  it  may  be  S,  Hg,  or  a  compound  of  As  or  Sb 

II.  HEATING  ON  CHARCOAL. — A  small  portion  of  the  substance 
is  placed  on  charcoal  and  exposed  to  the  inner  blow-pipe  flame. 
(See  page  69.)     If  an  infusible  white  residue  remains,  moisten  it 
with  Co(N03)2  ;  a  fine  blue  indicates  Al,  a  reddish  tint  Mg,  a  green 
color  Zn.     Mix  another  portion  with  Na2C03  and  heat  on  charcoal 
in  the  reducing  flame.     If  a  metallic  globule  is  formed  without  an 
incrustation,  it  indicates  Au,  Cu,  or  Ag,  as  the  color  is  yellow,  red,  or 
white.     A  very  fusible  and  malleable  globule  surrounded  by  a  yel- 
low incrustation  indicates  Pb  ;  if  the  incrustation  is  white  it  may  be 
Sn,  and  on  moistening  with  Co(N03j2  the  incrustation  turns  green. 
Bi  and  Sb  may  be  reduced  to  brittle  metallic  globules.     If  As  is 
present,  an  odor  resembling  garlic  is  noticed.     The  charcoal  tests 
will  be  of  little  use  to  the  student,  except  for  detecting  Ag  and  Pb, 
until  practice  has  given  him  considerable  facility  in  the  use  of  the 
blow-pipe. 

III.  BORAX  BEADS. — Several  metals  impart  characteristic  colors 
to  borax  glass  when  fused  with  it  before  the  blow-pipe.     The  opera* 
tion  is  a  very  simple  one,  and  many  of  the  beads  can  be  made  in 
even  an  ordinary  gas  or  alcohol  flame  without  the  use  of  a  blow- 
pipe.    The  end  of  a  piece  of  platinum  wire  is  bent  to  form  an  eye 
as  large  as  this  letter  O  ;  it  is  next  dipped  in  borax  and  held  in  the 
flame  until  fused,  then  dipped  in  the  powdered  substance  and  fused 
again.     Cr  in  O.F1.*  imparts  a  yellow  or  red  color  when  hot,  which 
becomes  yellowish  green  on  cooling  ;  in  R.F1.*  the  glass  is  green 
hot  and  cold.     Co  in  both  flames  blue.     Cu,  in  O.F1.  green  while  hot, 
blue  when  cold.     Fe  in  O.F1.  yellow  to  red  when  hot,  colorless  or 
yellow  when  cold  ;  in  R.F1.  bottle  green.     Mn  in  O.F1.  violet  or  ame- 
thyst  ;  in  R.F    becomes  colorless.  < 

*  O.F1.=  oxidizing  flame  ;  R.F1.=  reducing  flame  (page  92). 


218  QUALITATIVE     ANALYSIS. 


SOLUTION. 

The  first  thing  to  be  done  before  beginning  an  analysis  is  to 
bring  the  substance  into  solution.  Distilled  water  is  first  employed  ; 
if  a  residue  insoluble  in  water  remains,  it  is  treated  with  acid.  In 
analyzing  metals  and  alloys,  nitric  acid  is  the  usunl  solvent  ;  aqua 
regia  being  required  only  for  the  noble  metals.  If  Sn  is  present, 
and  Pb  and  Ag  absent,  HC1  is  employed.  Mineral  substances,  if 
insoluble  in  any  acid,  are  rendered  soluble  by  fluxing,  or  fusing 
with  pure  Na2C03  and  K2C0.3.  As  a  very  high  heat  is  required  for 
fluxing,  deflagration  is  sometimes  preferred.  One  part  of  the  insol- 
uble powder  is  intimately  mixed  with  two  parts  of  dry  sodium  car- 
bonate, two  parts  pulverized  charcoal,  and  twelve  parts  nitre.  The 
mixture  is  placed  in  the  open  air  and  a  match  applied.  A  portion 
of  the  porous  mass  produced  will  be  soluble  in  water,  the  remain- 
der in  acids.  The  two  solutions  are  to  be  preserved  and  tested 
separately.  The  metals  will  be  found  in  the  acid  solution,  while 
the  acids  will  be  found  in  the  aqueous  solution.  Before  beginning 
the  regular  course  of  analysis  with  these  solutions,  part  of  the 
aqueous  solution  is  evaporated  io  dryness  with  excess  of  HC1  to 
render  all  the  Si02  insoluble.  In  separate  portions  of  the  aqueous 
solution,  the  various  acids  are  sought  as  above  described  (p.  275). 

If  a  portion  of  the  substance  is  insoluble  in  HC1  after  fluxing,  it 
is  probably  silicic  acid,  or  an  undecomposed  silicate,  and  may  be 
rendered  soluble  by  fluxing  a  second  time. 

A  platinum  crucible  must  never  be  employed  if  reducible  metals, 
especially  Pb,  have  been  found  in  the  preliminary  tests. 

EXAMPLES     FOR     PRACTICE. 

AFTER  the  student  has  made  all  the  tests  above  given,  and  suc- 
ceeded in  separating  the  members  of  each  group  from  each  other, 
especial  care  being  given  to  the  separation  of  lead  from  bismuth, 
copper  from  cadmium,  arsenic  from  antimony,  and  nickel  from 
cobalt,  the  teacher  may  give  out  the  following  or  similar  substances 
for  analysis,  not  following  the  precise  order  of  the  book,  so  that  the 
student  shall  not  know  what  substance  he  is  analyzing.  Each  stu- 
dent should  record  the  results  of  every  analysis  in  a  note-book 
which  he  will  rule  for  each  analysis  as  shown  under  No.  I. 

1.  ANALYSIS  OF  CuS04. — A  crystal  of  this  salt  as  large  as  a  pea 


QUALITATIVE    ANALYSIS. 


is  given  to  a  student,  who  dissolves  it  in  distilled  water  in  a  test 
tube  and  divides  the  solution  in  two  portions.  To  one  is  added  a 
drop  of  HC1,  which  should  produce  no  precipitate.  H.2S  is  then 
added  until  all  the  Cu  is  precipitated.  It  is  then  filtered  and  the 
precipitate  thoroughly  washed  on  the  filter.  H2S  should  produce 
no  precipitate  in  the  filtrate.  The  precipitate  being  insoluble  in 
(NH4).»S,  is  dissolved  in  HN03,  and  no  residue,  except  perhaps  a 
little  sulphur,  remains,  so  that  the  absence  of  Hg  is  established. 
H2S04  produces  no  precipitate  in  this  solution,  neither  does 
NH4HO  ;  hence  Pb  and  Bi  are  also  absent.  The  ammonia,  however, 
gave  the  intense  blue  color  characteristic  of  Cu,  and  as  only  one 
metal  is  to  be  sought,  the  presence  of  Cu  is  farther  proved  by  adding 
HNO.j  and  K4FeCy6,  which  causes  a  reddish-brown  precipitate. 
The  second  portion  of  the  solution  is  used  in  testing  for  acids.  To 
a  small  quantity  of  this  some  BaCl2  is  added,  and  if  the  precipitate 
is  insoluble  in  HC1,  the  acid  present  must  be  H2S04.  The  results 
are  recorded  in  tabular  form  thus  :  * 

ANALYSIS  NO.  I. 

Substance  blue,  soluble  in  H2O. 


GROUP   I. 

GROUP   II. 

GROUP   III. 

GROUP   IV. 

GROUP  V. 

HC1 

H2S 

(NH4)2S 

(NH4)2C03 

o 

Brown    pre- 

o 

0 

O 

cip.,  sol.  in 

HN03. 

NH4HOblue. 

K4FeCy6 

brown. 

Cu. 

ACIDS  : 
BaCl2.     White  precipitate  insol.  in  HC1  .  .  .  .  H2S04. 

£.  ANALYSIS  OF  HgCl2. — This  salt  is  likewise  very  soluble  in 
H20.  To  one  portion  of  the  solution  add  HC1,  and  H2S.  The  lat- 
ter produces  a  black  precipitate,  insoluble  in  HN03,  which  indicates 
Hg,  but  a  confirmatory  test  must  be  employed,  which  is  to  dissolve 
the  precipitate  in  aqua  regia  and  add  SnCl2.  To  a  second  portion 


280  QUALITATIVE     ANALYSIS. 

add  some  BaCL,  which  will  cause  no  precipitate.  To  a  third  por- 
tion add  AgNO;!,  which  produces  a  white  precipitate  of  AgCl,  insolu- 
ble in  HN03,  but  soluble  in  NH4HO,  and  this  proves  that  the  acid 
is  HC1. 

3.  ANALYSIS  OF  FeS04. — Acidify  a  portion  of  the  solution  with 
HC1,  add  a  little  H2S  to  prove  that  no  metals  of  the  second  group 
are  present,  and  then  (NH4)2S,  which  produces  a  black  precipitate 
of  FeS,  which  is  treated  as  directed  for  Group  III,  page  272.  To 
some  of  the  original  solution  a  drop  of  K6Fe2Cy,2  is  added,  when 
the  blue  color  proves  the  presence  of  Fe.  The  acid  is  found  as  in 
No.  i  with  BaCl2. 

4>  ANALYSIS  OF  Sr(N03)2.  Dissolve  in  water,  test  for  Groups  I, 
II,  and  III,  which  may  occur  as  impurities,  and  then  add(NH4)2CO:j. 
This  white  precipitate  is  filtered  out  and  washed,  then  dissolved  in 
pure  HC1.  To  one  portion  add  2HF,SiF4  and  alcohol,  when  the 
absence  of  Ba  is  shown,  and  the  Sr  test  may  next  be  made,  by  add- 
ing NH4HO  and  CaS04.  The  precipitate  forms  slowly.  In  the 
original  solution  no  precipitate  is  formed  by  BaCI2  or  AgN03,  and 
a  careful  test  for  HN03  is  made  with  FeS04  and  H2S04,  as  de- 
scribed on  page  275. 

5.  ANALYSIS  OF  BaS04. — This  substance  refuses  to  dissolve  either 
in  H20  or  in  acids.     It  is  boiled  repeatedly  with  fresh  quantities 
of  Na2CO3  and  filtered  boiling  hot.     The  filtrate  contains  Na2S04  ; 
the  residue  is  BaCO;{  and  unaltered  BaS04.     The  residue  is  dis- 
solved in  HC1  and  tested  for  with  2HF,SiF4  or  SrC04  solution. 

6.  ANALYSIS  OF  A  COIN. — A  silver  coin  is  dissolved  in  HNO:J, 
then  diluted  and  the  Ag  precipitated  with  HC1  as  AgCl.     From  this 
metallic  silver  is  precipitated  on  a  piece  of  clean  zinc  placed  in  the 
precipitate  and  moistened  with  dilute  H2S04.     In  the  blue  filtrate 
will  be  found  all  the  copper,  which  may  be  tested  for  as  above.     If 
instead  of  a  silver  coin,  a  nickel  coin  is  used,  HC1  will  give  no  pre- 
cipitate, the  Cu  will  be  thrown  down  by  H2S,  and  the  Ni  by  (NH4)2S. 
In  analyzing  compound  substances,  great  care  must  be  taken  that 
all  the  metals  of  a  certain  group  are  precipitated  before  proceeding 
to  the  next,  and  for  this  purpose,  after  precipitating  the  Ag  with 
HC1,  a  drop  of  HC1  is  added  to  the  filtrate  to  ascertain  whether  any 
Ag  remains  in  solution. 

7.  ANALYSIS  OF  TYPE  METAL. — The  type  is  cleaned  and  dissolved 
in  nitric  acid.     If  a  white  insoluble  residue  remains,  it  may  contain 
both  tin  and  antimony.     To  the  filtered  and  diluted  solution  add 
just  enough  HC1  to  precipitate  all  fhe  Pb,  and  filter  cold.    To  tho 


QUALITATIVE     ANALYSIS.  281 

filtrate  add  H2S  as  long  as  a  precipitate  is  formed.  Filter  and  wash 
thoroughly,  digest  with  (NH4).2S  and  filter.  Dissolve  the  residue 
in  HNO3  and  test  for  Pb  and  Bi.  To  the  (NH4).2S  solution  add 
excess  of  HC1  to  ascertain  whether  any  portion  of  the  precipitate 
was  really  dissolved.  An  orange  red  precipitate  indicates  Sb,  which 
may  be  farther  tested  in  a  Marsh  apparatus.  The  white  residue, 
which  was  insoluble  in  HN03,  is  placed  in  a  porcelain  dish  in  con- 
tact with  a  slip  of  clean,  smooth  platinum  foil,  and  heated  with  a 
little  HC1.  H2O  is  then  added,  and  a  small  fragment  of  Zn  is  put 
into  the  liquid,  when  Sn  and  Sb  will  be  reduced  to  the  metallic  state. 
If  the  foil  is  blackened,  Sb  is  present.  The  metallic  residue  is  now 
dissolved  in  HC1,  and  HgCl2  is  added  to  ascertain  if  Sn  is  present. 

8.  ANALYSIS  OF  TEA-LEAD. — This  substance,  which  is  used  by  the 
Chinese  for  lining  tea-chests,  may  be  obtained  of  any  retail  grocer, 
or  tea  merchant.     It  consists  of  lead,  tin,  and  copper,  and  the  course 
of  analysis  differs  little  from  that  of  type  metal. 

In  addition  to  the  above  alloys,  tin-foil,  soft  and  hard  solder, 
German  silver,  and  Britannia  ware,  are  good  materials  to  prac- 
tice on. 

9.  ANALYSIS  OF  MIXED  SALTS. — A  mixture  of  Pb(N03)2,  Bi(N03)c, 
Co(NO.j)2>  KN03  may  be  dissolved  in  water  and  the  metals  sought 
in  the  above  order.     (See  Table,  page  284.)    In  testing  for  acids  the 
student  will   remember  that  if  Pb  was  found  among  the  metals, 
H2SO4  and  HC1  must  have  been  absent,  as  either  would  have  pre- 
cipitated the  lead.     If  the  student  forgets  this  and  adds  BaCl2  to 
the  solution,  it  will  form  a  precipitate  of  PbCl2,  which  he  might 
mistake  for  BaS04,  and  hence  incorrectly  suppose  H2S04  to  be 
present. 

Mixtures  of  various  other  soluble  salts  should  now  be  given  out, 
such  as  FeS04,  NaCl,  CuS04,  and  NH4C1  ;  gradually  increasing  the 
number  of  metals  and  acids  to  be  sought. 

10.  ANALYSIS  OF  LIME-STONE. — Dissolve  any  piece  of  marble  or 
lime-stone  in  HC1.     It  will  not  be  necessary  to  test  for  groups  I 
and  n;  a  small  portion  of  the  solution  is  tested  with  K4FeCy6  for 
iron.     The  alumina  generally  present  is  precipitated,  along  with 
the  iron,  by  NH4HO,  after  adding  NH4C1,  and  is  filtered  out  as 
rapidly  as  possible.     In  a  small  portion  of  the  filtrate  tests  are  made 
for  Ba  and  Sr,  which  are  of  course  absent,  so  that  all  the  Ca  may  be 
precipitated  by  oxalate  of  ammonia.      In  the  filtrate  Mg  will  be 
found  on  adding  Na2HPO4.     The  principal  acid  present  is  C02  as 
indicated  by  the  effervescence  with  HC1  when  first  dissolved.     If  a 


282  QUALITATIVE    ANALYSIS. 

residue  remained  insoluble  in  HC1,  it  is  probably  Si 02,  or  some 
silicate,  and  must  be  fluxed  with  Na2CO3  and  K2C03,  as  in  No.  12. 

11.  ANALYSIS  OF  BONE-DUST  AND  OTHER  PHOSPHATES. — A  piece 
of  burnt  bone  is  pulverized  and  mixed  with  a  little  ferric  chloride, 
or  iron  filings,  and  some  aluminum  chloride,  or  magnesium  phos- 
phate, to  make  variety.     The  solution  in  HC1  is  treated  with  NH4C1 
and  NH4HO  (see  Table,  page  274).     The  precipitate  is  boiled  with 
oxalic  acid  until  white  and  pulverulent,  which  indicates  that  the  Ca 
has  been  converted  into  an  oxalate,  and  is  allowed  to  cool.     When 
cold  sodium  acetate  is  added,  it  dissolves  the  Al,  Fe,  and  H3PO4 
and  the  residue  contains  Ca.      The  filtrate  is  boiled  with  NaHO 
until  the  Fe  and  Mg  are  precipitated,  and  the  filtrate  is  examined 
for  Al  and  H3P04,  the  test  for  the  former  being  NH4C1,  for  the  latter 
a  solution  of  MgS04  in  NH4C1  and  NH4HO.     The  precipitate  which 
contains  the  Mg  and  Fe  is  treated  with  NH4C1  to  dissolve  the  former, 
whose  presence  is  proven  if  Na2HPO4  produces  a  precipitate  in  the 
filtrate.     The  iron  is  dissolved  in  HC1,  and  K4FeCyti  added  ;  if,  how- 
ever,  Mn  or  Cr  are  suspected  of  being  present,  the  precipitate  must 
be  fused  with  Na2C03  and  KN03,  when  a  green  color  will  indicate 
Mn,  a  yellow,  Cr. 

12.  ANALYSIS  OF   CLAY,  SOIL,  AND   SILICIOUS  MINERALS  GENE- 
RALLY.— The  mineral  is  first  pulverized,  then  fused  with  Na2C03  + 
K2C03  and  dissolved  in  HC1  with  a  little  HN03,  and  evaporated 
to  dryness.     In  this  way  all  the  silica  present  is  rendered  insolu- 
ble ;  the  metals,  being  separated  as  oxides,  may  all  be  tested  for  in 
the  HC1   solution,   except  K  and  Na.     The   method  of  separating 
them  will  not  differ  from  the  ordinary  course  of  analysis  represented 
in  Table  L,  page  284. 

13.  ANALYSIS  OF  FELDSPAR. — This  mineral  consists  principally  of 
silicic  acid  combined  with  alumina  and  potash  or  soda.     It  is  in- 
soluble in  water  and  acids,  and  if  fluxed  with  Na2C03  and  K2C03 
it  would  not  be  possible  to  determine  whether  the  specimen  ana- 
lyzed were  a  potash  or  a  soda  feldspar.     In  this  and  similar  cases, 
where  the  alkalies  are  to  be  sought  in  siliceous  minerals,  a  differ- 
ent flux  must  be  employed.     An  intimate  mixture  is  prepared  of 
one  part  of  the  silicate,  six  parts  of  pure  precipitated  CaCO3,  and 
three-fourths  part  of  pulverized  NH4C1.     This  mixture  is  heated  to 
bright  redness  in  a  platinum  crucible  for  thirty  or  forty  minutes. 
The  crucible,  with  its  contents,  is  then  placed  in  a  beaker,  and 
soaked  for  half  an  hour  in  water  kept  near  the  boiling  point.     The 
contents  of  the  beaker  are  then  filtered.     The  filtrate,  containing 
Ca(HO)2,CaCl2  and  all  the  K  and  Na  of  the  original  silicate  as  chlo- 


QUALITATIVE    ANALYSIS. 

rides,  is  treated  with  a  little  NH4HO,  and  with  (NH4)2CO:,  in  slight 
excess  ;  the  liquid  is  heated  to  boiling  and  filtered.  This  second 
filtrate  is  evaporated  to  dryness,  and  gently  ignited  to  expel  ammo- 
nium salts.  The  residue  is  dissolved  in  a  little  water  ;  one  or  two 
drops  of  (NH 4)2  CO 3  and  a  drop  of  (NH  .)2C204  are  then  added  to 
remove  all  the  Ca  compounds  ;  the  mixture  is  again  heated  and 
filtered  ;  this  third  filtrate  is  evaporated  to  dryness  and  ignited. 
The  ignited  residue,  if  there  be  any,  consists  of  KC1  or  NaCl.  Some 
of  the  residue  is  placed  on  a  watch-glass,  PtCl4  added,  the  solution 
evaporated  almost  to  dryness,  and  a  little  dilute  alcohol  added.  If 
a  yellow  precipitate  remains,  K  is  present  ;  if  K  is  absent,  test  for 
Na  by  introducing  some  of  the  salt  on  a  clean  platinum  wire  into  a 
colorless  flame. 

14.  ANALYSIS  OF  HALOID  SALTS. — A  mixture  of  KI.KBr  and  NaCl 
is  well  suited  to  drill  the  student  on  the  detection  of  the  acids.     He 
will  probably  be  unable  to  find  them  all  without  some  assistance 
from  his  instructor.     A  part  of  the  mixture  is  dissolved  in  a  test- 
tube  and  some  CS2  poured  into  it.     A  little  Cl  water,  or  solution 
of  bleaching  powders,  is  then  poured  in  and  test-tube  well  shaken. 
The  I  is  liberated  and  dissolved  by  the  CS2,  imparting  to  it  the 
well-known  purple  color,  the  intensity  of  which  conceals  the  yellow- 
ish-brown color  of  the  Br  likewise   set  free   and   dissolved.     On 
adding  more  Cl  water,  the  violet  disappears,  leaving  only  the  Br  to 
color  the  ether.     To  detect  Cl  in  presence  of  both  I  and  Br,  the  dry 
powder  is  mixed  with    K2Cr207,  and   pure   concentrated   H2S04 
added,  and  heated,  when  CrO2Cl2  is  given  off  as  a  brownish-red 
gas  ;  and  a  glass  rod  dipped  in  NH4HO  and  held  over  the  tube 
becomes  slightly  yellow  if  Cl  is  present,  from  the  formation  of 
(NH4)2Cr04.     If  the  substance  to  be  tested  contains  only  Br  and  I, 
these  two  maybe  separated  by  CuSO4  and  H2SO3,  which  precipi- 
tates the  latter  as  Cu2I2   and  permits  the  use  of  the  starch  test 
for  Br. 

15.  ANALYSIS  OF  PRUSSIAN  BLUE. — The  student  who  is  ignorant 
of  what  substance  is  given  him  for  analysis,  on  finding  it  insoluble 
in  water  adds  HC1,  and  finds  this  does  not  destroy  the  color.     He 
will  then  naturally  suspect  Fe4(FeCy6):5,  and  hence  he  boils  a  por- 
tion of  the  original  substance  in  KHO,  which  destroys  the  color, 
but  leaves  a  precipitate.     After  diluting,  the  precipitate  is  filtered 
out  and  dissolved  in  pure  HC1  or  HN03  and  tested  for  Fe.     The 
filtrate  is  acidified  and  separate  portions  are  tested  for  H4FeCy6, 
with  CuS04,  and  Fe2Cl6  ;  the  former  should  give  a  reddish-brown 
precipitate,  the  latter  a  blue. 


884 


QUALITATIVE     ANALYSIS. 


TABLE    L— SCHEME    FOR 


rtdd  HC1  io  Solution. 
PREC. 

FILTRATE. 

Ag  Pb  Hg 
Boil  in  H20 
Sol.      Free. 

Add  HaS. 

PRECIPITATE. 

Pb 

W 

0 

b 

i 

o 

AgHg 
NH4HO 
Sol.Prec 

Hg  Pb  Bi  Cd  Cu  As  Sb  Sn  Au  Pt  S. 
Digest  with  (NH4)aS 
Residue.                                        Solution. 

%  With  HN03  white. 

Hg 

Hg  Pb  Bi  Cd  Cu 
BoU  in  HN03. 
Res.                    Sol. 

As  Sb  Sn  Au  Pt 
In  H  apparatus  with  Zn  &  HaSO4 
Gas.                Residue. 

Hg. 

& 
$ 

Pb  Bi  Cd  Cu 
With  HaSO4. 

Prec.                Sol. 

AsSb 
Pass  into 
AgNO, 

Sn  Au  Pt 
BoU  in  HC1. 

Sol.          Res. 

Pb 
? 

NH4HO 

As       Sb 
and 

Sn 

1 

P- 
Q 

AuPt 
HC1  and 
HN03. 

Bi 

Cd 
KCy 
H 
Prec. 

Cu 
and 

s 

"O 

I 
P 

Au        Pt 

P     § 

HH         ro 

1     1 

Cd. 
H 

a 

1 

Cu 

a 
p 

w 

CD 

T 

QUALITATIVE     ANALYSIS. 


285 


COMPLETE    ANALYSIS. 


FILTRATE. 


Add  H2  S. 

FELTRATE 


Add  NH4  HO  and  (NH,)ai 
Free. 


Filtrate. 


Co  Ni  Fe  Cr  Mn  U  Al  Zn 
Dilute  HC1. 

Add  (NH,)a  CO3. 
Free.                 Filtrate. 

Res.                             861. 

Ba  Sr  Ca 
Dissolve  in  HC1. 
Add2HF,  SiF4 

Co  Ni. 

Fe  Cr  Mn  U  Al  Zn 
Boil  in  Na  HO. 

MgKNa 
2  Parts. 

cr 

j.                             f,  r 

and  alcohol. 

<rr 

Jrrec.                          KMI. 

7.           77. 

^ 

Free.        Sol. 

Pi 
SaS 

Fe  Cr  Mn  U 
(NH4)2C03. 

Al 

a 

w 

Mg 

M 

•< 

Ba 

SrCa 

p 

Res.              Sol. 

3 

A. 

02 

| 

2  Parts. 

r               Tr 

P 

g| 

J 

Fe  Cr  Mn 

U 

o 

g 

? 

Y.              JY. 

0 

II 

Sr. 

Ca 

3 

M 

Fuse  with  KNO3 

^ 

? 

H 

3 

I 

andNaaCO3.  Dis- 
solve in  H2O. 

B 

D* 

p 

t2j 

"co 
p 

p 

ffl 

i 

Res.           Sol. 

w 

0 

B 

» 

0,3 

c? 

ES 

Fe 

Cr 

Mn 

^ 

? 

1 

CD 

>5$ 

PJ 

ciT 

10 

W 

^, 

o 

? 

O 

§ 

CO 

i 

ra 

e 

I 

1 

p 

^ 

S" 

?> 

p 

s 

P 

P 

p 

1 

Hi 

£1 

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QUALITATIVE     ANALYSIS. 


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QUALITATIVE  ANALYSES.  287 

LIST    OF    REAGENTS. 


THE  following  reagents  are  required  for  the  above  course  of  QUALITATIVE 
ANALYSIS.  They  should  be  kept  in  tightly  stopped  bottles,  labelled  and  num- 
bered as  below.  Sets  of  printed  labels  with  formulas  may  be  had  of  dealers  iu 


1.  Hydrochloric  Acid  (concent.)  ..................  HC1. 

2.  Hydrochloric  Acid  (dilute)  .....................  HC1. 

*3.  Nitric  Acid  (concent.)  .........  .................  HNO.. 

4.  Nitric  Acid  (dilute)  .............................  HNOS. 

*5.  Sulphuric  Acid  (concent.)  ......................  H.,SO4. 

6.  Sulphuric  Acid  (dilute)  .........................  H^SCv 

*7.  Hydrosulphuric  Acid  .........................  H2S. 

*8.  Sodium  Hydrate  ...............................  NaHO. 

9.  Sodium  Carbonate  (solution)  ...................  Na2CO3. 

10.  Ammonium  Hydrate  ...........................  NH4HO. 

11.  Ammonium  Carbonate  ......................  (NH4}aCO». 

12.  Ammonium  Chloride  ...........................  NH4Cl. 

13.  Ammonium  Sulphide  .........................  (NH4)aS. 

14.  Ammonium  Oxalate  ...........................  (NH4)aCaO4. 

15.  Barium  Chloride  ........   ......................  Bad,, 

16.  Hydro-di-sodic  Phosphate  .....................  Na.,HPO4. 

17.  Potassium  Ferrocyanide  .....................  K4FeCye. 

18.  Potassium  Ferricyanide  ........................  KnFeaCyia. 

19.  Potassium  Iodide  _____  ..........................  KI. 

20.  Acetic  Acid  ....................................  C2H4Oa. 

21.  Calcium  Sulphate  (solution)  ....................  CaSO4. 

22.  Mercuric  Chloride  (poison)  .....................  HgCla. 

23.  Stannous  Chloride  (protochloride  of  tin)  ........  SnCl2. 

24.  Sodium  Acetate  ................................  NaC2H3O,. 

25.  Hydrofluosilicic  Add  .........................  2HF,SiF4. 

26.  Potassium  Bichromate  .........................  K»Cr2OT. 

27.  Magnesium  Sulphate  ..........................  MgSO4. 

28.  Lime  Water  .................................  Ca(HO)2,=CaO,HaO. 

29.  Calcium  Chloride  ............................  CaCl2. 

30.  Lead  Acetate  (sugar  of  lead)  ...................  Pb(C2H3Oa)a. 

*3i.  Tartaric  Acid  ..................................  C4HBO0. 

*32.  Silver  Nitrate  ..................................  AgNO3. 

33.  Platinum  Chloride  ............................  PtCl4. 

34.  Ammonium  Molybdate  ........................  (NH4)2MoOt  (  +  nitric  acid). 

35.  Potassium  Sulphocyanide  ......................  KCyS. 

36.  Potassium  Nitrite  .............................  KNOa. 

The  following  are  kept  in  the  dry  state,  in  wide-mouth  bottles: 

37.  Sodium  Carbonate,  pure  .......................  Na.jCO3. 

38.  Borax  .........................................  2NaBO2,B2O3  +  ioHaO. 

39.  Potassium  Nitrate  ..............................  KNO3. 

*4o.  Potassium  Cyanide  (poison)  ....................  KCy. 

41.  Ferrous  Sulphate  ..............................  FeSO4. 

42.  Calcium  Hypochlorite  (bleaching  powders). 

43.  Ferrous  Sulphide  ..........  ....................  FeS. 

44.  Zinc  ..........................................  Zn. 

45.  Red  Lead. 

*  The  labels  on  the  acids  may  be  protected  with  paraffine,  and  the  stopper  in 
NaHO  bottle  is  also  covered  with  it  to  prevent  sticking.  Fresh  solutions  of 
H..S  and  C4H6O8  must  frequently  be  prepared  (see  page  210,  note).  KCy  is 
only  dissolved  as  used,  and  must  b"e  handled  with  great  care.  AgNO,  is  usually 
kept  in  a  black  bottle. 


288 


QUALITATIVE     ANALYSIS. 


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QUESTIONS  FOR  CLASS  USE. 


I.  — INTRODUCTION. 

Page  17. — Define  chemistry.  Illustrate.  What  is  the  distinction 
between  organic  and  inorganic  chemistry?  Illustrate.  What  is  an 
element  ?  How  many  are  known  ?  Is  it  probable  that  all  the  ele- 
ments have  been  discovered  ?  Define  chemical  affinity.  Illustrate. 
How  does  it  act? 

18. — How  can  we  find  what  elements  will"  combine  ?  What  is  a 
compound?  Are  compounds  like  their  elements?  Illustrate. 
What  is  the  action  of  heat  ?  Of  light  ?  Of  solution  ?  Illustrate. 

19. — State  the  principles  upon  which  the  elements  are  named. 
Illustrate  each.  What  are  chemical  symbols?  How  are  the  sym- 
bols formed  ?  Define  atomic  weight.  Illustrate. 

21. — State  the  four  laws  of  the  atomic  theory.  What  is  the  molec- 
ular weight  of  a  compound  ?  What  is  a  binary  compound  ?  Which 
element  js  placed  first  in  reading  the  symbol  of  a  compound  ?  In 
writing  ?  In  reading  the  name  ?  Name  the  three  variations  from 
these  rules.  What  is  the  use  of  the  terminations  -ide?  -uret?  De- 
fine an  oxide.  Define  the  different  compounds  of  0. 

22. — What  is  an  acid  ?  Must  an  acid  always  be  sour  ?  Name 
one  that  is  not  (page  no).  What  is  the  test?  How  does  the  ter- 
mination of  an  acid  indicate  its  strength  ?  What  is  the  meaning  of 
the  prefix  per? — hypo?  How  are  the  hydracids  named? 

23. — Define  a  base.  An  alkali.  What  is  the  reciprocal  influence 
of  th«  alkalies  and  the  acids?  Define  a  salt.  How  is  it  named? 
What  is  the  difference  between  an  -ous  and  an  -ic  salt  ?  What  is 
a  formula  ? 

24. — What  signs  are  used  ?  To  what  is  the  proportion  of  an  ele- 
ment in  any  compound  always  equal  ?  The  weight  of  an  element  ? 
State  the  proportion  to  be  used  in  solving  problems. 


QUESTIONS     FOR     CLASS     USE.  291 

I  I.  — I  N  O  R  G  A  N  I  C      CHEMISTRY. 

1.  — THE      NON-METALS. 

OXYGEN. — Give  the  symbol  and  atomic  weight  of  oxygen.  What 
is  the  meaning?  What  other  element  is  an  acid-former? 

28. — Name  the  sources  of  O.  Do  these  fractions  indicate  weight 
or  volume?  How  is  0  prepared  from  potassium  chlorate  and 
manganese  dioxide?  Give  the  reaction.  What  becomes  of  the 
potassium  chloride? 

29. — What  is  the  use  of  the  black  oxide  of  manganese  ?  Define 
catalysis.  Name  the  properties  of  0.  What  is  oxidation  ?  An 
oxide  ?  Show  that  0  is  a  supporter  of  combustion.  What  com- 
pounds are  formed  in  these  illustrations?  What  is  an  anhydride? 
An  acid  ? 

31-32.— Describe  the  destructive  effects  of  the  0  in  the  air.  What 
causes  the  decay  of  peaches?  Why  does  not  canned  fruit  decay? 
Describe  the  action  of  0  on  fuel.  On  the  teeth.  On  impure  water. 
On  writing-ink.  On  red-hot  iron.  On  damp  knives  and  forks. 
How  is  river-water  purified  on  a  sea-voyage  ? 

33.— By  what  means  is  the  0  carried  through  the  system  ?  What 
work  does  it  perform  in  the  body  ?  Why  is  the  blood  in  the  arte- 
ries red  and  in  the  veins  purple  ?  What  chemical  processes  are 
included  by  the  .chemist  under  the  term  oxidation  ? 

34. — Does  fire  differ  from  decay  ?  Is  heat  always  produced  by 
oxidation  ?  Illustrate.  Describe  the  body  as  a  furnace. 

35. — What  is  the  chemical  process  of  starvation?  Why  does 
unusual  exercise  cause  one  to  breathe  more  rapidly?  Why  does 
running  cause  panting?  Why  do  we  need  extra  clothing  when  we 
sleep,  even  at  midday,  in  the  summer  ?  How  do  hibernating  ani- 
mals illustrate  this  ?  How  does  a  cold-blooded  animal  differ  from 
a  warm-blooded  one  ?  How  does  O  give  us  strength  ? 

36. — How  are  action  and  reaction  equal  in  chemistry  as  in  phil- 
osophy ?  What  is  potential  force  ?  Dynamic  force  ?  Show  how  O 
is  constantly  burning  the  body.  Is  there  any  part  of  the  body  that 
is  permanent?  Illustrate  the  rapidity  of  this  change.  Show  the 
truth  of  the  paradox — "  We  live  only  as  -we  die." 

37. — Why  do  we  need  food  and  sleep?  Show  how  0  acts  as  a 
scavenger  in  nature.  In  what  sense  is  0  the  sweeper  of  the  body? 
Is  this  a  useful  provision  ? 


292      ^     QUESTIONS     FOR     CLASS     USE. 

SS.— How  much  0  does  each  adult  need  per  day?  Total  amount 
used  daily?  What  would  be  the  result  if  the  air  were  pure  0? 
What  objects  would  escape  combustion?  What  is  ozone?  Where 
is  it  seen  ? 

39. — Preparation  ?  Properties  ?  Test  ?  Is  it  a  valuable  constit- 
uent of  the  air  ?  What  is  antozone  ?  Its  characteristic  ? 

NITROGEN. — Symbol  and  atomic  weight?  Why  so  called? 
Sources  ?  Preparation  ? 

43. — Properties  ?  Why  does  a  person  drown  in  water  ?  Would 
a  person  die  in  pure  N  ?  What  is  the  peculiarity  of  the  nitrogen 
compounds  ?  What  causes  flesh  to  decompose  so  much  more  easily 
than  wood  ?  Does  the  N  we  take  in  at  each  breath  do  us  any  direct 
good  or  harm  ?  Where  do  we  get  N  to  make  our  flesh  ? 

43. — What  use  do  plants  make  of  the  N  they  breathe  in  through 
their  leaves  ?  Describe  the  action  of  N  and  0  in  our  stoves.  Where 
do  plants  obtain  N  ?  State  the  main  distinction  between  O  and  N. 
What  is  the  office  of  the  N  in  the  air  ?  Show  that  the  proportion  of 
O  and  N  in  the  atmosphere  gives  us  the  golden  mean. 

44> — Symbol  and  molecular  weight  of  nitric  acid  ?  Common 
name  ?  Explain  its  occasional  presence  in  the  atmosphere.  Prep- 
aration? Why  is  its  symbol  HNO3  and  not  N206  ?  Show  that  in 
its  salts  an  acid  takes  the  place  of  the  H. 

45. — Properties  ?  Has  it  been  obtained  as  a  solid  ?  How  does  it 
rank  in  strength?  What  color  does  it  give  to  wood?  Uses? 
Explain  its  oxidizing  action.  What  is  aqua  regia%?  Describe  the 
process  of  etching.  The  action  of  HNO3  on  Sn.  What  are  the  red 
fumes  which  pass  off?  How  does  HN03  illustrate  the  power  of 
chemical  affinity? 

46. — Symbol  and  molecular  weight  of  nitrous  oxide?  The  com- 
mon name  ?  Preparation  ?  Reaction  ?  Properties  ?  For  what 
purpose  has  liquid  nitrous  oxide  been  used  ?  (Philosophy,  p.  242.) 
What  is  the  effect  of  nitrous  oxide  on  the  human  system  ?  State  its 
use  in  surgical  operations.  Symbol  and  molecular  weight  of  nitric 
oxide?  Its  preparation ?  Why  is  the  gas  in  the  jar  colorless? 

47. — What  compound  is  formed  ?  Properties  of  NO?  What  are 
the  fumes  which  it  forms  in  the  air  ?  Symbol  and  molecular  weight 
of  ammonia?  Why  so  called  ?  Its  old  name? 

48.— What  is  aqua  ammonia?  Whence  obtained ?  Give  the  reac- 
tion. Properties  ? 

49.— Prove  that  H3N  is  an  alkali.  What  is  its  test?  Its  antidote? 
How  liquefied  ?  Define  the  nascent  state. 


QUESTIONS     FOR     CLASS     USE. 

HYDROGEN. — Symbol  and  atomic  weight  ?  Meaning  of  the  name  ? 
Preparation  ? 

51. — Reaction  ?  What  compound  is  formed  ?  Properties  ?  Is  H 
a  metal?  Ans. — In  all  reactions  it  plays  the  part  of  a  metal,  and 
like  most  of  the  metals  is  electro-positive.  The  size  of  its  atoms  ? 
Its  levity  ?  Will  it  destroy  life  ?  Effect  on  the  voice  ?  Use  in  fill- 
ing balloons  ? 

52. — What  is  the  product  of  the  combustion  of  H  ?  What  is  the 
philosopher's  lamp?  What  are  the  mixed  gases?  What  is  the 
cause  of  the  report  ?  Will  the  gases  combine,  if  mixed  ?  Describe 
the  hydrogen  gun. 

54. — What  compound  is  formed  by  the  combustion  of  H  ?  What 
becomes  of  the  H2O?  What  is  the  action  of  platinum  sponge  on  a 
jet  of  H?  What  becomes  of  this  force?  Describe  Dobereiner's 
lamp.  Explain  the  heat  produced  by  burning  H. 

55. — How  are  hydrogen  tones  produced  ?     Explain. 

WATER. — What  is  the  freezing  and  the  boiling  point  of  water  ? 
How  is  the  composition  of  water  proved  ?  Why  does  the  black- 
smith sprinkle  water  on  his  forge  fire  ? 

57-8. — What  injury  may  a  small  quantity  of  H20  do,  if  thrown  on 
afire?  Explain.  Can  H20,  then,  be  burned?  Show  that  electri- 
cal force  is  latent  in  water.  What  becomes  of  this  force  ?  Illustrate 
the  abundance  of  H20  in  the  animal  world.  Vegetable  world. 
Mineral  world. 

59. — Why  will  blue  vitriol  lose  its  color  if  heated?  What  is 
"  burnt  alum  ?  "  Water  of  crystallization  ?  Show  the  adaptation  of 
H30  as  a  solvent.  What  water  is  the  purest  ?  Why  does  rain-water 
taste  so  insipid  ? 

60. — Is  river  water  a  healthy  drink  ?  What  is  hard  water  ?  Soft 
water  ?  Why  does  the  hardness  of  water  vary  in  different  places  ? 
Is  hard  water  healthful  ?  How  may  we  detect  organic  matter  in 
H2O?  What  minerals  are  most  common  in  water?  What  is  the 
"fur"  in  a  tea-kettle?  Why  does  soap  curdle  in  hard  water? 

61-2. — What  is  the  cause  of  the  tonic  influence  of  the  sea-breeze  ? 
How  could  Salt  Lake  be  freshened  ?  What  is  the  use  of  the  air  in 
H2O?  How  do  fish  breathe  ?  Why  does  the  air  in  water  contain 
so  much  O  ?  Why  is  boiled  water  so  insipid  ?  Give  some  of  the 
paradoxes  of  water.  Name  the  various  uses  of  water.  (Philosophy, 
P.  255.) 

CARBON. — Symbol  and  atomic  weight  ?    Illustrate  the  abundance 


QUESTIONS    FOR     CLASS     USE. 

of  C.  Is  it  more  characteristic  of  the  vegetable  than  of  the  mineral 
kingdom  ?  What  are  its  three  forms  ? 

65. — Proof  of  these  allotropic  states?  What  is  an  allotropic  con- 
dition ?  What  is  the  diamond  ?  Properties  ?  Has  it  ever  been 
made  artificially  ?  What  is  a  carat  ? 

66. — How  is  the  diamond  ground  ?  Describe  the  three  modes  of 
cutting.  What  gives  the  diamond  its  value  ? 

67. — Common  name  for  graphite?  Origin?  Uses?  Describe 
the  process  of  making  a  lead-pencil.  What  is  a  black-lead  cruci- 
ble? What  is  British  Lustre?  Gas  carbon?  How  is  charcoal 
made? 

68. — What  is  the  chemical  change  ?  Illustrate  the  durability  of 
charcoal  ? 

69. — Its  property  of  absorbing  gases.  Its  preservative  effects. 
Its  filtering  properties.  (Philosophy,  p.  41.)  What  do  you  mean 
by  the  deoxidizing  or  reducing  action  of  C  ?  Application  to  the 
arts? 

70. — What  is  soot  ?  What  causes  the  burning  of  chimneys  ?  Does 
this  occur  oftener  when  wood  than  when  coal  is  used  as  fuel  ?  How 
is  lampblack  made ?  Uses?  Fitness  for  printing ?  What  can  you 
say  about  ancient  MSS.  ?  How  is  boneblack  made?  Uses?  How 
is  sugar  refined  ? 

71. — Describe  the  formation  of  coal.  Difference  between  bitu- 
minous and  anthracite  coal.  Why  is  coal  found  in  layers,  with  slate, 
etc.,  "between  ?  Why  is  the  coal  hidden  in  the  earth  ?  What  proof 
have  we  that  coal  is  of  vegetable  origin  ? 

72. — What  is  coke?  Uses?  Describe  the  formation  of  peat. 
Uses?  What  is  muck?  Use?  Name  some  of  the  diverse  proper- 
ties and  uses  of  C. 

CARBONIC  ANHYDRIDE.  —  Symbol  and  molecular  weight? 
Sources?  How  it  is  constantly  formed  ? 

74. — Preparation  ?     Reaction  ? 

75. — Test  ?  What  causes  the  pellicle  on  lime-water  ?  What  does 
this  show?  Prove  that  we  exhale  C03.  Give  the  properties  of  CO,,. 

76. — Prove  that  CO2  is  heavier  than  air.  A  non-supporter  of 
combustion.  That  it  contains  C.  What  test  should  be  employed 
before  descending  into  a  deep  well  or  an  old  cellar  ?  How  can  you 
remove  the  foul  air  ? 

77.— Tell  about  the  Grotto  del  Cane.  Is  CO,  directly  poi- 
sonous? What  is  choke-damp?  Fire-damp?  Which  is  more 
dreaded  ? 


QUESTIONS    FOR     CLASS     USE.  295 

78. — Has  CO. 2  been  used  in  extinguishing  fires?  Tell  about  the 
absorption  of  C02  by  H20.  What  is  soda-water? 

79.— How  is  CO 2  liquefied  ?  Why  does  the  liquid  acid  solidify 
when  exposed*to  the  air  ?  What  principle  in  philosophy  does  this 
illustrate?  How  low  a  degree  of  cold  has  been  produced  in  this 
manner  ?  Describe  the  need  of  ventilation.  How  is  the  air  expired 
from  our  lungs  made  useful  ? 

80. — Is  a  single  opening  sufficient  to  ventilate  a  room  ?  What 
practical  application  do  you  make  of  this  subject?  Symbol  and 
molecular  weight  of  carbonic  oxide  ?  Properties  ? 

81. — Where  do  we  often  see  it  ?  How  is  CO  formed  in  a  coal- 
fire  ?  Practical  importance  of  this  fact  ?  What  causes  the  unpleas- 
ant odor  of  coal-gas  ?  Symbol  and  molecular  weight  of  light  car- 
buretted  hydrogen ?  Properties?  How  is  it  formed ? 

82. — Name  the  places  where  it  is  found  in  great  quantities. 
Symbol  and  molecular  weight  of  heavy  carburetted  hydrogen  ? 
Properties  ? 

83. — What  gases  mainly  compose  coal-gas  ?  Which  is  the  most 
valuable?  Describe  the  manufacture.  Is  the  odor  beneficial ?  Is 
coal-gas  explosive?  Why  is  the  jet  flat?  When  we  turn  the  gas 
very  low,  or  the  supply  is  insufficient,  why  is  the  flame  blue  ?  Sym- 
bol and  molecular  weight  of  cyanogen?  Meaning  of  the  name  ? 

84. — Preparation  ?  What  are  its  compounds  called  ?  What  is 
the  yellow  prussiate  of  potash  ?  The  red  ?  Ans. — The  ferricyanide, 
K3FeCy6.  Properties  of  Cy?  What  is  a  compound  radical?  Sym- 
bol of  hydrocyanic  acid  ?  Common  name  ?  Where  found  ?  Anti- 
dote ?  What  are  the  fulminates?  How  are  gun-caps  made? 

COMBUSTION. — Define.  What  is  a  combustible  ?  A  supporter  of 
combustion?  .(The  difference  between  these  two  is  nicely  shown  in 
the  experiment  with  H  on  p.  52.)  A  burnt  body  ?  Ans. — A  body 
which  has  combined  with  0. — Example  :  a  stone,  water.  Upon 
what  does  the  amount  of  heat  produced  by  combustion  depend  ? 
The  intensity?  Why  do  we  need  a  draught  to  a  stove?  What  is 
meant  by  the  igniting  point  of  a  substance  ?  Does  combustion,  in 
its  chemical  sense,  commence  before  the  fuel  catches  fire  ?  Why  do 
we  use  "  kindlings "  in  starting  a  fire  ?  Why  can  we  light  pitch- 
pine  so  easily?  What  are  hydrocarbons?  What  are  the  ordinary 
products  of « combustion  ?  What  causes  the  dripping  of  stove- 
pipes ?  What  are  the  ashes  ?  Why  does  fresh  fuel  produce  a 
flame? 

86. — Show  how  wisely  C  is  adapted  for  a  fuel,    What  would  be 


QUESTIONS    FOR     CLASS     USE. 

the  effect  if  C02  were  not  a  gas  ?  Define  flame.  Describe  the 
burning  of  a  candle. 

87.— Show  that  flame  is  hollow.  What  causes  the  light  ?  Why  is 
the  flame  blue  at  the  bottom  ?  Products  of  comb«stion  ?  Tests  ? 
Why  does  the  wick  turn  black  ? 

88. — What  causes  the  coal  at  the  end  of  the  wick  ?  Why  does 
snuffing  brighten  the  light  ?  Why  does  a  draft  of  air,  or  a  sudden 
movement  of  the  candle,  cause  a  deposit  of  soot  ?  Why  is  the  flame 
of  a  candle  or  lamp  red,  or  yellow?  Ans. — Because  the  heat  is  not 
sufficient  to  cause  the  carbon  to  emit  all  the  rays  of  the  spectrum. 
Use  of  plaited  wicks?  Object  of  a  chimney  to  a  lamp? 

89. — A  flat  wick  ?  Advantage  of  an  Argand  lamp  ?  What  is  the 
film  which  gathers  on  the  chimney  when  the  lamp  is  first  lighted  ? 
Why  does  this  soon  disappear?  Why  do  tar,  spirits  of  turpentine, 
etc.,  burn  with  much  smoke  ?  Why  does  alcohol  give  much  heat 
and  no  smoke  ?  Describe  Davy's  safety-lamp.  Illustrate  this  by  a 
wire  gauze  over  the  flame  of  a  candle. 

90. — Describe  Bunsen's  burner.  Why  does  it  give  great  heat, 
little  light,  and  no  smoke?  Describe  the  oxy-hydrogen  blow-pipe. 

91. — Why  does  it  give  great  heat  and  little  light  ?  What  is  the 
calcium  light  ? 

92. — Describe  the  mouth  blow-pipe.  The  three  parts  in  the  blow- 
pipe  flame.  What  is  the  reducing  flame  ? 

93. — The  oxidizing  flame  ?  Why  does  blowing  on  a  candle-flame 
extinguish  it  ?  Why  does  water  put  out  a  fire  ?  Give  illustrations 
of  spontaneous  combustion. 

THE  ATMOSPHERE. — Name  the  constituents.  Proportion.  State 
the  comparison.  What  is  the  law  of  diffusion  ? 

97. — What  effect  does  this  have  on  the  air?  Is  the  air  a  chemical 
compound?  Illustrate.  Has  each  constituent  a  special  use? 
Name  the  uses  of  O.  Of  C02. 

98. — Explain  the  chemical  change  which  takes  place  in  the  leaf. 
What  force  separates  the  C  from  the  0  ?  What  is  the  influence  of 
house-plants  upon  the  atmosphere  of  a  room  ?  What  do  you  say  of 
the  exact  balance  kept  between  the  wants  of  animals  and  plants  ? 

100. — What  relation  exists  between  animals  and  plants  ?  Which 
gathers  and  which  spends  the  solar  force  ?  Which  performs  the 
office  of  reduction  ?  Which  that  of  oxidation  ?  How  is  the  solar 
force  set  free  ?  What  is  the  use  of  the  watery  vapor  in  the  air  ? 

101. — Which  of  the  constituents  are  permanent  ?    Is  this  a  wise 


QUESTIONS    FOR     CLASS     USE.  297 

provision  ?  Why  ought  the  vapor  to  be  easily  changed  to  the  liquid 
form  ?    What  effect  does  this  permanence  have  upon  sound  ? 

THE  HALOGENS. — Name  them.  Symbols  and  atomic  weights. 
Compare  the  halogens  with  each  other.  What  compounds  do  they 
form  ?  Why  is  chlorine  so  called  ?  Source  ? 

103. — Preparation  ?  Reaction  ?  Properties  ?  What  action  does 
Cl  have  on  phosphorus,  arsenic,  etc.  ?  Why  does  a  solution  of  the 
gas  soon  become  acid  ?  What  is  its  action  on  organic  bodies  ?  On 
turpentine  ?  On  printers'  ink  ?  Describe  the  chemical  change  in 
domestic  bleaching. 

104. — The  method  of  bleaching  on  a  large  scale.  What  is  the 
advantage  of  using  Cl  over  other  disinfectants?  How  may  the  gas 
be  set  free  ? 

105. — How  are  hospitals  punned  ?  What  mixture  would  liberate 
Cl  in  the  greatest  quantities?  Symbol  and  molecular  weight  of 
hydiochloric  acid?  Common  name?  Preparation?  Reaction? 
Properties?  What  is  muriatic  acid?  What  are  its  compounds 
termed?  Tests?  What  is  nitro-muriatic  acid? 

106. — Symbol  and  molecular  weight  of  chloride  of  lime?  'Uses? 
Symbol  and  molecular  weight  of  calcium  chloride  ?  Preparation  ? 
Peculiar  property  ?  Tell  what  you  can  about  bromine.  Its  uses. 
What  is  the  peculiarity  of  fluorine  ?  Source  ?  What  acid  does  it 
form?  For  what  is  this  acid  noted?  Describe  the  process  of  etch- 
ing with  HF. 

•  107. — Why  is  not  HF  kept  in  ordinary  bottles?  Is  it  dangerous 
to  use?  Why  is  iodine  so  called?  Preparation?  Properties? 
For  what  are  its  compounds  noted  ?  How  may  its  stains  be 
removed  ?  Test  ?  Use  in  medicine  ? 

BORON. — Symbol  and  atomic  weight?  Source?  Describe  the 
scene  in  Tuscany  where  it  is  found.  Process  of  manufacture. 

109. — Symbol  and  molecular  weight  of  borax?  Uses  in  solder- 
ing, and  in  softening  hard  water  ? 

SILICON.  —  Symbol  and  atomic  weight?  Source?  Common 
names  ?  What  gems  does  it  form  ?  What  is  sand  ?  Properties  ? 

110. — Why  is  it  called  an  acid  ?  Is  silica  soluble  in  H20  ?  How 
does  it  get  into  plants  ?  In  what  plants  is  it  found  ?  Explain  the 
process  of  petrifaction.  What  is  said  of  the  antiquity  of  glass? 
Pliny's  story  of  its  origin  ?  What  is  said  of  its  value  in  the  twelfth 
century? 

111. — Name  the  four  varieties  of  glass  and  the  composition  of 
each.  What  are  the  essential  ingredients  of  glass  ?  How  is  glass 


QUESTIONS    FOR     CLASS     USE. 

colored  ?  Name  the  oxides  used.  Why  is  flint-glass  so  called  ? 
How  is  glass  annealed  ?  Describe  the  Prince  Rupert's  drop. 

112. — How  are  Venetian  balls  made  ?     Tubes  ?     Beads  ? 

SULPHUR. — Symbol  and  atomic  weight  ?  Sources  ?  What  is  the 
principle  of  hair-dyes  ?  Why  do  eggs  tarnish  silver  spoons  ?  What 
is  the  difference  between  brimstone  and  flowers  of  sulphur  ?  Prop- 
erties? Solvent?  Three  allotropic  forms?  Describe  the  amor- 
phous state. 

114. — Uses  of  S  ?  Symbol  and  molecular  weight  of  sulphurous 
anhydride  ?  Where  is  it  familiar  ?  What  are  its  compounds  called  ? 
Uses  in  bleaching?  Why  are  new  flannels  liable  to  turn  yellow 
when  washed  ?  Symbol  and  molecular  weight  of  sulphuric  anhy- 
dride ?  By  what  other  name  is  it  known  ?  Preparation  ?  Prop- 
'erties  ?  Why  is  Nordhausen  acid  so  called  ? 

115-16. — Symbol  and  molecular  weight  of  sulphuric  acid  ?  Com- 
mon name?  State  its  importance.  What  are  its  compounds 
called?  Illustrate  the  making  of  H2S04.  Describe  its  manufacture. 
Reaction. 

117. — Properties?  What  especial  property?  Illustrate.  Its 
strength  ?  Color  of  its  stain  on  cloth  ?  How  removed  ?  On  wood  ? 
Cause  of  this  action?  Test?  Symbol  and  molecular  weight  of  hy- 
drogen sulphide  ?  Where  is  it  found  ? 

118. — Preparation?  Reaction?  Properties?  Use?  Color  of 
these  precipitates  ?  Test  ?  Symbol  and  molecular  weight  of  carbon 
sulphide  ?  Preparation  ?  Properties  ?  Uses  ?  How  does  it  illus- 
trate the  force  of  chemical  affinity? 

PHOSPHORUS. — Symbol  and  atomic  weight  ?    Why  so  called  ? 

120. — Source  ?  In  what  parts  of  the  body,  and  in  what  forms,  is 
it  found  ?  Preparation  ?  Properties  ?  Caution  to  be  observed  ? 
Is  phosphorus  poisonous?  What  is  the  product  of  its  combus- 
tion? 

121. — Describe  the  amorphous  form  of  phosphorus.  What  is  the 
principal  use  of  phosphorus?  .  Describe  the  making  of  the  lucifer 
match.  The  safety  match.  What  compounds  are  formed  in  the 
burning  of  a  match  ? 

122. — What  is  phosphorescence  ?  Its  cause  ?  Symbol  and  molec- 
ular weight  of  hydrogen  phosphide?  Source?  Preparation? 
Properties? 

ARSENIC. — Symbol  and  atomic  weight  ?  Common  name  ?  Test  ? 
What  is  commonly  sold  as  arsenic  or  ratsbane?  Preparation  of 
arsenious  acid  ?  Properties  ?  What  can  you  tell  of  its  antiseptic 


QUESTIONS    FOR     CLASS     USE.  299 

property?    Antidotes?     Describe  Marsh's  test.     How  can  the  As 
be  distinguished  from  Sb?*     What  is  said  of  arsenic  eating? 

2.  — THE      METALS, 

POTASSIUM.— Symbol  and  atomic  weight  ?  History  of  its  discov- 
ery? Source?  How  do  we  get  our  supply?  Preparation? 

127. — Properties  ?  How  must  it  be  kept  ?  Reaction  when  thrown 
on  H20  ?  Symbol  and  molecular  weight  of  potash  ?  Of  potassium 
hydrate?*  Properties?  Its  feel?  Its  affinity  fpr  H2O  and  C02  ? 
Uses?  Symbol  and  molecular  weight  of  potassium  carbonate? 
Common  name  ? 

128. — Preparation?  What  part  of  the  tree  furnishes  the  most 
potash?  What  is  the  derivation  of  the  word?  Symbol  and  molec- 
ular weight  of  hydrogen  potassium  carbonate?  Common  names? 
Preparation?  Define  a  rational  formula.  Illustrate.  An  empirical 
formula?  Illustrate.  What  is  a  neutral  salt?  An  acid  salt?  A 
dibasic  acid  ? 

129. — Symbol  and  molecular  weight  of  potassium  nitrate  ?  Com- 
mon names  ?  Where  is  it  found  ?  How  is  it  prepared  artificially  ? 
How  much  water  would  be  required  to  dissolve  a  pound  of  this 
salt  ?  Properties  ?  Uses  ?  What  is  the  composition  of  gunpowder  ? 
Cause  of  its  explosive  force  ? 

130. — Uses  of  potassium  chlorate?  Potassium  bichromate? 
Composition  of  fire-works? 

SODIUM.— Symbol  and  atomic  weight  ?  Source?  What  propor- 
tion does  it  form  of  common  salt  ?  What  element  does  it  resemble  ? 

131. — Reaction  when  thrown  on  water?  What  compound  is 
formed  ?  Test  ?  Symbol  and  molecular  weight  of  common  salt  ? 
What  use  does  it  subserve  in  the  body?  Is  salt  abundant?  De- 
scribe the  manufacture. 

132. — What  is  solar  salt  ?  Describe  the  "  hopper-shape  "  crystal. 
Is  it  b^st  to  heat  the  water  for  dissolving  salt  ?  What  is  a  saturated 
solution? 

133. — Symbol  and  molecular  weight  of  sodium  'sulphate  ?  Com- 
mon name  ?  Preparation  ?  Reaction  ?  What  curious  property  has 
this  salt?  Why  will  the  dropping  in  of  a  crystal  cause  solidification  ? 

*  Antimony  is  more  likely  to  be  mistaken  for  arsenic  than  for  any  other  metal. 
The  crust  which  is  formed  by  decomposing  antimoniuretted  hydrogen  in  Marsh's 
apparatus  does  not  yield  octahedra,  when  sublimed  in  a  tube  with  air,  but 
prisms.  The  metal  is  also  easily  soluble  in  yellow  ammonium  sulphide,  which  is 
nearly  without  effect  upon  arsenical  crusts.— MILLER. 


300  QUESTIONS    FOR     CLASS     USE. 

Symbol  and  molecular  weight  of  sodium  carbonate?  Common 
names?  Why  called  carbonate  of  soda? 

184- — Describe  its  manufacture.  Why  will  Na2S04  soften  hard 
water?  Symbol  and  molecular  weight  of  hydrogen  sodium  carbon- 
ate? Common  name?  Why  called  bicarbonate  of  soda ?  Prepara- 
tion? Use?  What  is  an  empirical  formula ?  A  rational  formula? 
Give  the  theory  of  ammonium.  How  is  the  symbol  H4N,HO  ob- 
tained ?  What  is  a  compound  radical  ?  A  compound  halogen  ? 

135. — Symbol  and  molecular  weight  of  ammonium  •  chloride  ? 
Preparation?  Uses?  Symbol  and  molecular  weight  of  ammonium 
carbonate?  Common  names?  Uses?  Symbol  and  molecular 
weight  of  ammonium  nitrate ?  Preparation?  Uses?  What  is  the 
sodium  amalgam? 

CALCIUM. — Symbol  and  atomic  weight ?  Source?  In  what  part 
of  the  body  is  it  found  ?  In  what  form  do  we  commonly  see  it  ? 
Symbol  and  molecular  weight  of  lime  ?  Preparation?  Describe  a 
lime-kiln.  Properties  of  CaO  ?  Test  ? 

137. — What  is  the  difference  between  "  water-slacked  "  and  "  air- 
slacked  "  lime  ?  Uses  ?  What  is  whitewash  ?  Concrete  ?  Hard- 
finish  ?  Calcimining?  Theory  of  the  hardening  of  mortar  ?  Why 
are  newly-plastered  walls  so  damp?  Will  mortar  harden  if  pro- 
tected from  the  air?  Action  of  lime  on  the  soil  ?  Will  it  not  lose 
its  beneficial  effect  after  a  time  ?  Should  it  be  applied  to  a  compost 
heap?  How  can  this  waste  be  avoided?  How  would  you  test  for 
the  escaping  H3N?  Action  of  lime  on  copperas?  How  does  ,the 
copperas  get  in  the  soil  ? 

138. — Uses  of  lime?  Symbol  and  molecular  weight  of  carbonate 
of  lime?  Source?  How  are  stalactites  and  stalagmites  formed? 

139.— What  is  petrified  moss?  Whiting?  Marble?  Chalk? 
Marl  ?  Symbol  and  molecular  weight  of  calcium  sulphate  ?  Com- 
mon names?  What  is  plaster  of  Paris?  Why  does  plaster  of  Paris 
harden,  if  moistened  ?  Ans. — Because  it  absorbs  water  again. 
Uses?  What  is  plaster?  How  prepared  for  use  as  a  fertilizer ? 
Ans. — It  is  ground  into  a  fine  powder.  Tell  the  story  of  Franklin. 

140. — What  is  the  difference  between  sulphate  and  sulphite  of 
lime  ?  Symbol  and  molecular  weight  of  phosphate  of  lime  ?  What 
is  the  superphosphate?  Use?  Uses  of  the  salts  of  barium  and 
strontium  ?  What  is  heavy  spar  ?  Bary tes  ? 

MAGNESIUM. — Symbol  and  atomic  weight?  Source?  How  can 
you  tell  if  a  stone  contains  Mg?  Ans. — It  generally  has  a  soapy 
feel.  Properties  ?  For  what  is  it  noted  ?  Name  the  two  classes  of 


QUESTIONS    FOR     CLASS     USE.  801 

rays  contained  especially  in  its  light  (Philosophy,  p.  206).  For  what 
purposes  do  the  colorific  rays  adapt  it  ?  Does  it  contain  heat-rays 
also  ?  Ans. — Very  few.  Product  of  its  combustion  ?  Symbol  and 
molecular  weight  of  magnesium  carbonate  ?  Magnesium  sulphate  ? 
Common  name  ? 

ALUMINUM. — Symbol  and  atomic  weight  ?  Common  name  ? 
Source?  Properties?  Solvent?  What  can  you  say  of  its  abund- 
ance and  probable  usefulness?  What  is  alumina ?  What  crystals 
and  gems  does  it  form  ?  What  is  emory  ?  Symbol  and  molecular 
weight  of  silicate  of  alumina?  Common  name  ?  Source ? 

144. — Use  in  the  soil?  In  the  arts?  What  is  ochre?  Fuller's 
earth  ?  Explain  the  process  of  glazing  pottery  ware.  What  is  the 
salt  glaze?  The  litharge  glaze?  What  objection  to  the  latter? 
What  gives  color  to  brick  ?  What  is  the  peculiarity  of  white  brick  ? 
How  is  alum  made  ? 

145. — Name  the  different  kinds  of  alum.  Which  kind  is  the  com- 
mon commercial  alum  ?  Use  of  alum  in  dyeing  ?  How  are  alum 
crystals  made?  Ans. — They  are  obtained  by  suspending  threads  in 
a  saturated  solution  of  this  salt.  In  this  manner  alum  baskets, 
bouquets,  etc.,  are  formed  of  any  desired  color.  What  is  spectrum 
analysis?  Is  it  a  reliable  test?  Illustrate  its  delicacy?  What  is 
the  spectroscope  ? 

IRON. — Symbol  and  atomic  weight?  Tell  what  you  can  of  its 
value  to  the  world.  How  is  its  use  a  symbol  of  a  nation's  pro- 
gress ? 

149. — State  how  its  value   is   enhanced   by  labor.      Name   the 
sources  of  iron.     Common  ores.     Describe  the  process  of  smelting 
iron  ore.     Why  is  hot  air  used  for  the  blast  ?      Reaction  of  the  • 
lime? 

151. — What  becomes  of  the  0  in  the  ore  ?  Origin  of  the  term 
"  pig-iron?  "  Name  the  varieties  of  iron.  Difference  between  them. 
What  is  cast-iron ?  Its  properties?  Uses?  What  exception  adapts 
iron  for  use  in  castings  ?  What  does  this  teach  us  ?  What  is  chilled 
iron?  Wrought  iron? 

152. — Preparation?  Effect  of  jarring?  How  is  Fe  tempered? 
Illustrate  its  malleability.  What  is  steel  ?  Preparation  ?  In  mak- 
ing steel  tools,  how  does  the  workman  judge  of  the  temper?  How 
are  cheap  knives  made? 

153. — Describe  Bessemer's  process.  Cause  of  the  changing  col- 
ors often  seen  in  the  scum  over  standing  water  ? 

254. — Name  the  different  oxides  of  iron.     Give  the  symbol  of 


QUESTIONS    FOR     CLASS     USE. 

each.  Where  is  each  found  ?  Origin  of  colored  sand  ?  What 
peculiar  property  is  possessed  by  the  ferric  oxide  and  ferric  hy- 
drate ?  What  is  iron  carbonate  ?  By  what  name  is  it  known  ? 

155.  —  Cause  of  the  ferruginous  deposit  around  chalybeate 
springs  ?  Symbol  and  molecular  weight  of  iron  bisulphide  ?  Com- 
mon names?  Of  ferrous  sulphate?  Preparation?  Uses?  What 
is  chameleon  mineral  ? 

ZINC. — Symbol  and  atomic  weight?  Source?  Preparation? 
Reaction?  Is  it  malleable?  Will  it  oxidize  in  the  air?  Uses? 
What  is  philosopher's  wool  ?  What  is  galvanized  iron  ?  Are  water- 
pipes  made  of  this  material  safe  ?  Symbol  and  molecular  weight  of 
zinc  oxide  ?  Use  ?  Symbol  and  molecular  weight  of  zinc  sulphate  ? 
Use? 

TIN. — Symbol  and  atomic  weight  ?  Where  found  ?  Properties  ? 
What  is  the  "  tin  cry  ?  "  What  is  common  tin-ware  ?  Action  of 
HNO:l  on  Sn  ?  What  can  you  say  of  the  manufacture  of  pins  ? 

COPPER. — Symbol  and  atomic  weight?  Where  found?  Antiquity 
of  the  mines  ?  What  is  malachite  ?  Properties  of  Cu  ?  Color  of 
its  vapor?  How  tempered  ?  Test?  What  is  verdigris?  Carbon- 
ate of  copper  ?  Black  oxide  of  copper  ?  What  is  the  danger  of 
using  a  copper  kettle  ?  Solvent  of  Cu  ?  Test  ?  Symbol  and  molec- 
ular weight  of  copper  sulphate  ?  Common  name  ?  Uses  ? 

LEAD. — Symbol  and  atomic  weight?  Source?  Preparation? 
Properties  ?  Its  effect  on  the  human  system  ?  On  water  ?  Is  there 
more  danger  with  hard,  or  with  soft  water?  What  precaution 
should  always  be  used  with  lead  pipes  ?  What  is  the  test  of  lead  ? 
What  is  "  litharge  ?  "  Its  uses  ?  "  Red-lead  ?  "  Its  uses  ?  What  is 
"  white-lead  ?  "  Describe  its  manufacture.  With  what  is  it  adul- 
terated ?  What  is  "  sugar  of  lead  ?  "  Properties  ?  Antidote  ? 
Explain  the  formation  of  the  lead-tree. 

GOLD. — Symbol  and  atomic  weight?  Source?  Preparation? 
What  is  an  amalgam  ?  Quartation  ?  Properties  ?  Solvent  ?  Pro- 
cess of  making  gold-leaf? 

SILVER. — Symbol  and  atomic  weight  ?  Source  ?  Preparation,  i, 
from  the  sulphide  ;  2,  horn-silver  ;  3,  lead  ?  Describe  the  process 
of  reduction  at  the  West.  What  is  cupellation  ?  Properties  ?  Sol- 
vent? Test?  What  is  the  common  name  of  nitrate  of  silver? 
What  is  its  action  on  the  flesh  ?  How  may  its  stain  be  removed  ? 
Uses  ?  Of  what  are  hair-dyes  and  indelible  inks  made  ?  Describe 
the  process  of  Daguerreotyping.  Photography. 

PLATINUM. — Symbol  and  atomic  weight  ?    Source  ?    Preparation  ? 


QUESTIONS     FOR     CLASS     USE.  803 

Properties  ?  Uses  ?  Why  is  iridium  so  named  ?  What  is  iridos- 
mine  ?  How  is  platinum  wire  made  ? 

MERCURY. — Symbol  and  atomic  weight  ?  Common  name  ?  Why 
so  called?  Source?  Preparation?  Properties?  Uses?  Action 
on  the  human  system?  Process  of  silvering  mirrors?  What  is 
blue-pill  ?  Mercurial  ointment  ?  Symbol  of  mercuric  oxide  ?  Mer- 
curous  chloride?  Mercuric  chloride?  Common  name?  Uses? 
Properties  ? 

THE  ALLOYS. — What  is  an  alloy  ?  What  peculiarity  with  regard 
to  the  melting  point  ?  Of  what  is  type-metal  made  ?  Pewter  ? 
Britannia  ?  Brass  ?  German  silver  ?  Solder  ?  Fusible  metal  ? 
Bronze?  How  is  gold  soldered  ?  Silver?  Copper?  What  is  the 
principle?  What  are  the  constituents  of  gold  coin  ?  Silver  coin? 
What  is  the  meaning  of  the  term  carat  ?  How  are  shot  manufac- 
tured ?  How  are  they  sorted  ?  What  is  oreide  ?  Aluminum 
bronze  ?  Compare  the  properties  of  the  metals  with  regard  to,  i, 
oxidation  ;  2,  density  ;  3,  melting  point  ;  4,  color  ;  5,  malleability  : 
6,  brittleness  ;  7,  tenacity  ;  8,  special  properties. 

II.  — ORGANIC       CHEMISTRY. 

INTRODUCTION. — Why  must  matter  be  organized  ?  What  is  the 
office  of  plants  ? 

182. — What  is  the  difference  between  organic  and  inorganic 
bodies  ?  Illustrate  each  of  the  four  distinctions. 

183. — What  is  the  number  of  carbon  compounds  ?  Define  isomer- 
ism.  Illustrate.  What  is  the  cause  ?  Allotropism  ?  Illustrate. 

STARCH. — Symbol  and  molecular  weight?  Sources?  Use  in  the 
plant  ?  Why  stored  in  that  form  ?  Appearance  under  the  micro- 
scope ?  Preparation?  Properties?  What  is  dextrine?  Test  of 
starch  ?  Varieties  ?  What  is  gum  ?  Composition  ?  Mucilage  ? 
Is  it  soluble  in  water  ?  What  is  pectose  ?  Pectin  ? 

WOODY  FIBRE. — Symbol  and  molecular  weight  ?  What  is  the 
composition  of  wood  ?  Name  the  various  forms  of  cellulin.  Illus- 
trate the  wonders  of  secretion.  State  the  uses  of  woody  fibre.  The 
making  of  paper.  Paper-parchment.  Linen.  Cotton.  Gun-cotton 
[C6H7(N02)305].  Collodion.  Its  uses.  Cane-sugar.  How  is 
sugar  refined  ?  Difference  between  loaf  and  granulated  sugar  ? 
Describe  a  centrifugal  machine.  What  is  terra  alba  ?  Use  ?  Of 
what  are  gum  drops  made?  Rock-candy?  What  is  caramel? 
Use?  Symbol  and  molecular  weight  of  grape-sugar ?  Source? 


SOJf.  QUESTIONS    FOR     CLASS     USE. 

Sweetening  power?  How  is  sugar  made  from  starch?  How  does 
the  oil  of  vitriol  act?  How  do  jellies,  preserves,  etc.,  "candy?" 
Why  are  dextrose  and  levulose  so  named  ? 

FERMENTATION. — Cause?  Does  it  ever  take  place  spontane- 
ously ?  How  does  the  yeast  act  ?  What  change  takes  place  in  the 
alcoholic  fermentation?  The  acetic?  Describe  the  formation  of 
yeast.  The  making  of  malt.  Yeast  cakes.  The  varieties  of  fer- 
mentation. What  is  gluten  ?  How  does  it  act  ?  What  is  diastase  ? 
Describe  the  brewing  of  beer.  Why  is  lager  beer  so  called  ?  De- 
scribe the  making  of  wine.  What  is  the  difference  between  a  dry, 
a  sweet,  and  an  effervescing  wine?  Cause  of  the  flavor?  State  the 
proportion  of  alcohol  in  common  liquors.  How  is  brandy  made  ? 
Rum?  Whisky?  Gin?  Describe  the  apparatus  used  for  distilla- 
tion. Symbol  and  molecular  weight  of  alcohol  ?  What  is  said  of  its 
affinity  for  water  ?  What  is  absolute  alcohol  ?  Name  the  uses  of 
alcohol  in  the  arts.  Effects  of  alcohol  on  the  human  system.  Sym- 
bol and  molecular  weight  of  ether?  Is  it  properly  called  sulphuric 
ether?  (See  p.  203.)  Preparation?  Properties?  Uses?  Prep- 
aration of  chloroform?  Properties?  Uses?  What  is  chloral? 
Chloral  hydrate  ?  Properties  ?  Uses  ?  Symbol  and  molecular 
weight  of  acetic  acid  ?  What  is  the  glacial  acid  ?  Preparation  of 
vinegar?  What  causes  the  working  of  cider  ?  What  change  takes 
place?  Properties  of  acetic  acid  ?  Use  ?  What  causes  the  "  work- 
ing "  of  preserves  ?  What  is  aldehyde  ?. 

ORGANIC  RADICALS. — What  is  a  radical  ?  A  homologous  series  ? 
Name  the  terms  of  the  marsh-gas  series.  What  is  ethyl,  methyl, 
etc.  ?  By  what  other  name  is  marsh-gas  known  ?  Describe  the 
formation  of  the  alcohols.  By  what  other  name  is  common  alcohol 
known?  State  the  formation  of  the  aldehydes  and  acids.  The 
ethers?  The  compound  ammonias.  The  salts  of  the  radicals. 
Uses. 

DESTRUCTIVE  DISTILLATION. — What  change  takes  place  in  the 
decay  of  wood  ?  Effect  upon  the  soil  ?  What  change  takes  place 
in  the  distillation  of  wood?  Why  is  it  called  "destructive?" 
What  is  pyroligneous  acid ?  Use?  Creosote?  Properties?  Uses? 
Paraffine  ?  Properties  ?  Uses  ?  How  is  tar  made  ?  What  are  the 
products  of  the  distillation  of  coal-tar  ?  Properties  of  carbolic  acid  ? 
What  are  the  picrates?  Uses?  What  is  benzole?  Benzine? 
Properties  ?  Uses  ?  What  is  phenyl  alcohol  ?  What  is  nitro-ben- 
zole  ?  What  are  the  coal-dyes  ?  Give  an  account  of  their  discovery 
and  properties.  What  is  naphtha?  Naphthaline?  Anthrocene? 


QUESTIONS    FOR     CLASS     USE.  305 

Alizarin?  Dead-oil?  Uses?  Petroleum?  How  formed?  De- 
scribe its  distillation.  The  rectification  of  kerosene.  Danger  of 
kerosene  explosions.  The  test  given  by  Dr.  Nichols.  How  is  bitu- 
men formed  ?  Describe  Tar  Lake.  What  is  "  Greek  fire  ?  " 

THE  ORGANIC  ACIDS. — Where  is  oxalic  acid  found?  Prepara- 
tion? Properties?  Antidote?  Uses?  Where  is  tartaric  acid 
found  ?  Preparation  ?  What  is  cream  of  tartar  ?  Tartar  emetic  ? 
Rochelle  salt?  Seidlitz  powders?  Where  is  malic  acid  found? 
Citric?  Tannic?  Name  its  varieties.  What  are  nut-galls  ?  Prop- 
erties of  tannin  ?  Describe  the  process  of  tanning.  How  is  leather 
blackened  ?  How  is  ink  made  ?  Why  does  writing-fluid  darken 
by  exposure  to  the  air?  What  is  gallic  acid ?  Pyrogallic ?  Use? 

THE  ORGANIC  BASES. — Sources  ?  What  is  opium  ?  Preparation  ? 
Uses?  Laudanum?  Paregoric?  Danger  of  opium-eating ?  What 
is  morphine  ?  Use  ?  Quinine  ?  Use  ?  Nicotine  ?  Properties  ? 
Strychnine?  Properties?  The  chromatic  test?  Name  the  active 
principle  of  tea  and  coffee.  What  substances  are  found  in  tea  ?  In 
coffee?  Describe  the  process  of  tea-raising.  Of  making  black  tea. 
Green  tea. 

ORGANIC  COLORING  PRINCIPLES. — Source  ?  What  is  an  adjective 
color  ?  A  substantive  color  ?  A  mordant  ?  The  process  of  dyeing  ? 
Of  calico  printing?  What  is  madder?  Its  coloring  principle? 
Cochineal?  Use?  Brazil-wood?  Use?  Indigo?  Preparation? 
White  indigo  ?  Logwood  ?  Litmus  ?  Leaf-green  ? 

OILS  AND  FATS. — Name  the  two  classes.  What  is  the  difference 
between  them?  What  is  the  composition  of  the  fatty  bodies? 
Illustrate.  What  is  glycerin ?  Uses?  Nitro-glycerin ?  Illustrate 
the  formation  of  soap.  What  is  the  reaction  ?  Difference  between 
hard  and  soft  soap?  What  is  the  cause  of  the  curdling  of  soap  in 
hard  water  ?  Describe  the  cleansing  action  of  soap.  What  is  sapon- 
ification  ?  How  is  stearin  made  ?  What  are  adamantine  candles  ? 
Is  wax  of  animal  or  vegetable  origin  ?  How  is  it  bleached  ?  What 
is  a  drying  oil  ?  Boiled  oil  ?  Putty  ?  Printers'  ink  ?  Cod-liver 
oil  ?  Croton  oil  ?  Castor  oil  ?  Sweet  oil  ?  Uses  ?  Sources  of  the 
volatile  oils ?  Preparation?  Composition?  Name  the  three 
classes.  Illustrate  each.  What  is  oil  of  turpentine?  Rosin? 
Camphene  ?  Camphor  ?  Preparation  ?  Properties  ? 

RESINS  AND  BALSAMS. — What  is  the  difference  between  a  resin 
and  a  balsam?  Illustrate.  Source?  Properties?  Uses?  What 
is  rosin  ?  Preparation  ?  Uses  ?  Lac  ?  Source  ?  Preparation  ? 
Shellac?  Sealing-wax?  Gum  Benzoin ?  Uses?  Amber?  Origin? 


806  QUESTIONS    FOR     CLASS     USE. 

Properties?  Uses?  India-rubber?  Source?  Properties?  Uses? 
What  is  vulcanized  rubber?  Properties?  Gutta-percha?  Uses? 

ALBUMINOUS  BODIES.* — Name  them.  What  is  their  composi- 
tion? What  is  albumen  ?  Source?  Properties?  Casein?  Why 
does  milk  curdle?  Action  of  rennet?  Why  does  cream  rise  on 
milk?  Describe  the  souring  of  milk.  What  is  gelatin?  Glue? 
Isinglass  ?  Size  ?  Fibrin  ?  Properties  ?  Gluten  ?  Legumin  ? 
Putrefaction  ?  Cause  ?  Why  does  salt  preserve  meat  ? 

DOMESTIC  CHEMISTRY. — Describe  the  chemical  changes  which 
take  place  in  making  bread.  What  is  stale  bread  ?  Why  is  it  dry  ? 
How  is  aerated  bread  made  ?  Why  is  bread  ever  sour  ?  How  are 
griddle-cakes  raised  ?  Biscuit?  What  are  baking-powders?  Ac- 
tion of  soda  and  HCI  ?  Of  sal-volatile?  How  is  bread  changed  by 
toasting?  How  are  potatoes  changed  by  cooking? 

*  Notice  here  the  wise  provision  of  nature.  Nitrogen,  slow  and  sluggish  when 
uncombined,  is  fitted  to  dilute  the  air  ;  while  N,  restless  and  uneasy  when  com- 
bined, is  equally  adapted  to  form  unstable  compounds  of  food,  to  carry  force 
into  our  bodies  and  there  to  quickly  set  it  free.  Oxygen,  when  free,  is  active, 
eager,  and  ready  to  search  the  nooks  and  crannies  of  the  capillaries ;  but  when 
once  it  combines  with  a  substance,  takes  it  for  better  or  for  worse,  and  forms  the 
stablest  of  compounds.'  We  find  nitrogen  compounds  in  the  animal  and  vegeta- 
ble worlds,  ready  for  use  where  they  are  needed,  in  our  muscles.  Oxygen  com- 
pounds are  abundant  in  the  mineral  world,  and  stored  in  the  seeds  of  plants,  at 
hand  to  give  form  to  the  more  permanent  parts  of  the  body.  Such  profound 
relations,  such  nice  adaptations  of  our  bodies  to  the  world  around,  give  us 
glimpses  of  a  creative  skill  worthy  our  noblest  thought  and  highest  admiration. 


NEW  ^ND  ENLARGED  SET 


CHEMICALS    AND    APPARATUS, 

Prepared  expressly  for,  and  adequate  to,  the  performance  of  all  the  experiments 
in  the  new  edition  of  Steele's  Fourteen  Weeks  in  Chemistry.     Price  $40. 

CU:EM:IC.AJL.S. 


1    qt. 


Alcohol, 
Alum, 

Ammonia  (nqna  ammonia), 
Ammonium  Chloride, 
"  Nitrate, 

Aniline, 

Antimony  Metallic, 
Antimony  Tartrate, 
Arsenious  Anhydride. 
Barium  Chloride, 
Bleaching  Powder, 
Bone-black, 
Calcium  Sulphate, 
Camphor, 
Carbon  Bisulphide, 
Cobalt  Nitrate, 
Copper  Sulphate, 
Ether  Sulphuric, 
Fluor  Spar, 
Gold-leaf, 
Gun  Colton, 
Hydrochloric  Acid, 
Indigo, 
Iodine, 
Iron  Sulphate  (Copperas), 

"     Sulphide, 
Lead  Acetate, 

"    Oxide  (Litharge), 
Litmus, 


1  Glass  Funnel,  4-in. 

1  •'      Alcohol  Lamp,  4-oz. 

2  Evaporating  Dishes. 

1  Retort  Stand,  two  rings. 
12  Test  Tubes,  assorted. 
1  Wedgewood  Mortar  and  Pestle. 

1  Jewelers'  Blow-Pipe. 

2  Hard  Glass  Tubes,  each  3  ft.  long,  one  1  in.  in 

dinm.,  and  one  <£  in. 

1  Piece  Iron-Wire  Gauze,  4  in.  sq. 

1  Three-Cornered  File. 

1  Round  File. 

1  Piece  Platinum  Wire,  6  in.  long. 
64  Corks,  assorted  sizes. 
1  Evolution  Flask,  Funnel  and  Delivery  Tube. 


Magnesium  Ribbon, 
Manganese  Dioxide, 
Mercury  Chloride  (corrosive  sublimate), 


6  in. 
4  oz. 
1  dr. 

30  grs. 


>|dr. 
1  stick. 


4  oz. 
1  oz. 
1  oz. 


grs. 


1    oz. 

4    oz. 

20  grs. 

4    oz. 

21bs. 

Idr. 

Idr. 

20  grs. 


1  Florence  Flask,  pint,  with  Delivery  Tube. 

4        "  "2  4-oz.,  1  8-oz.,  and  1  12-oz. 

6  Rubber  Connectors,  assorted  sires. 

1  Deflagrating  SpSon. 

}4  Ib.  French  Glass  Tubing,  assorted. 

1  Lead  Tray. 

1  Measuring  Glass,  Common. 

1  Pair  Scales,  with  Set    of  Weights,  metric   and 

common. 

6  Sheets  Filtering  Paper. 
1  Hessian  Crucible,  4-oz. 
1  Pipette. 

1  3-gal.  Gas-Bag,  with  Stop-Cock. 
1  Set  Tin  Cork-Borers. 


\t  oz 
1*  ox.' 

Mercury  Cyanide, 
Mercuric  Oxide, 

15  grs. 

Nitric  Acid, 

20\rs. 

Nut-galls,  Ground. 
Oxalic  Acid, 

20  grs. 

Phosphorus, 

20  gra. 

Platinum  Spongy, 

2    oz. 

Potassium  Metallic, 

1    oz! 

Bichromate, 
Chlorate, 

1   dr. 

Ferrocvanide, 

1   dr. 

Hydrate  (Caustic  Potash), 

20  grs. 

Iodide, 

KOI. 

Nitrate, 

2    oz. 

Permanganate, 

Silv     Nitrate, 

1  square. 

Sod    m, 

20  grs. 

Biborate  (Borax), 

1    Ib. 

Carbonate, 

20  grs. 

Sulphate, 

15  grs. 

Strontium  Nitrate, 

ft 

Sulphur  (Brimstone), 
Sulphuric  Acid, 

1    oz. 

Tartaric  Acid, 

iO  grs! 

Turpentine,  Oil  of, 
Zinc  Chloride, 

J£3P~  The  above  (chemicals  and  apparatus)  are  neatly  packed  for  transporta- 
tion in  one  box,  and  furnished  at  $40  for  the  complete  set,  by  the  publishers  of 
Steetfs  Chemistry. 


The  following  additional  apparatus  may  be  also  procured,  if  desired,  at  the 
prices  annexed  • 

1.  FOR  MAKING  O.     Copper  Retort,  with  Iron  Stand,  Gas-Bag,  Rub- 

ber Tubing,  and  Gallows  Screw  Connectors  ...........................  $25.50 

2.  FOR  MAKING  AND  INHALING  N2O.     Wash-Bottle,  Large  Rub- 

ber Bag,  Small  Bag  with  stop-cock  and  mouth-piece,  i  Ib.  Ammonium 
Nitrate  (H4N,NO,)  ...  ......................    22.50 

3.  COMPOUND  BLOW-PIPE.    2  Rubber  Gas-Bags,  viith  tubing,  con- 

nectors, and  jet,  complete  ........      ...................................   40.00 

4.  THE  ARTICLES  in  Nos.  i,  2,  and  3,  complete  ........................    70.00 

The  following  can  be  easily  obtained,  viz.  :  Sheet  zinc  and  copper,  old  watch- 

springs,  starch,  marble,  lime,  charcoal,  scraps  of  tin,  packing  bottles,  soda,  salt, 
sugar,  beeswax,  pails,  wire,  candles,  soap,  plates,  junk  bottles,  and  iron,  zinc, 
and  steel  filings. 

1STOTICK. 

Remittance  should  accompany  order  for  apparatus.  If  desired,  however,  it 
will  be  sent  "  C.  O.  D."  to  customers  inclosing  ten  per  cent,  of  the  amount 
Money  sent  by  P.  O.  money-order,  or  draft  on  N.  Y.,  is  at  our  risk. 


808 


CHE3IICALS     AND     APPARATUS. 


For  those  who  prefer  a  cheaper  set  we  still  continue  to  supply  the  following 
chemicals  and  apparatus  adequate  to  the  performance  of  experiments  in  the  old 
edition  of  Steele  s  Fourteen  Weeks  in  Chemistry.  Price,  $20. 


CHEMICALS. 

V  lb.   Black  Oxide  of  Manganese. 

}£  oz.  Chloride  of  Barium. 

%  "     Blenching  Powder. 

4    "     Ammonia. 

Chlorate  of  Potash. 

%  "     Tartaric  Acid. 

L? 

Alum. 

%  "     Chloride  of  Mercury. 

1  ' 

Sulphur. 

*|  "    Metallic  Antimony. 

8 

Caustic  Potash  (Sticks). 
Sugar  of  Lead. 

yz  "    Arsenious  Acid. 
%  "    Iodide  of  Potassium. 

i   ^ 

z.  Bichromate  of  Potash. 

%  "    Iodine. 

2 

Bone-Black. 

%  "     Potassium. 

2 

Sulphide  of  Iron. 

%  "    Sodium. 

1 

Nitrate  of  Potash. 

%"    Solution  Chloride  of  Platinur 

Chloride  of  Ammonium. 

4    "    Sulphuric  Ether. 

ly 

Yellow  Prussiate  of  Potash. 

%  "    Chloride  of  Cobalt  Solution. 

1^ 

Red              "                " 

\i  "    Bisulphide  of  Carbon. 

% 

Oxalic  Acid. 

%  "    Phosphide  of  Calcium. 

3 

Ground  Nut-galls. 
Phosphorus, 

1     "    Litharge. 
^  «    Nitrate  of  Silver  Solution. 

i 

Fluor  Spar. 
Litmus. 
Magnesium  Ribbon. 

1    "    Sulphate  of  Iron. 
1     "     Sulphate  of  Copper. 
}4  dr.  Gun  Cotton  for  Collodion. 

1  Specimen  Metal,  Aluminum. 

6  sheets  Filtering  Paper. 

1  Funnel-4-in. 

1  Alcohol  Lamp— 1-oz. 

2  Evaporating  Dishes. 
1  Tripod. 

6  Assorted  Test  Tubes. 

1  Mortar  and  Pestle. 

1  Mouth  Blow-Pipe  (Jewellers'). 

1  Ring  Platinum  Sponge. 


1  Stop-Cock  and  Connertor  for  Bladder  Gas-Bag. 

2  Tubes  for  Hydrogen  Tones. 
%  lb.  French  Glass  Tubing. 

1  ft.  Rubber  Tubing  for  Connectors. 

1  Small  Lead  Tray. 

1  Evolution  Flask,  Funnel,  and  Delivery  Tube. 

1  Florence  Flask  with  Delivery  Tube. 

1  Deflagrating  Spoon. 


The  above  (chemicals  and  apparatus)  are  neatly  packed  for  transpor- 
tation in  one  box,  and  furnished  at  $20  for  the  complete  set,  by  the  publishers  of 
Steele'  s  Chemistry. 


The  following  additional  apparatus  may  be  also  procured,  if  desired,  at  the 
prices  annexed  : 

1.  FOR  MAKING  O.    Copper  Retort,  with  Iron  Stand,  Gas-Bag,  Rubber 

Tubing,  and  Gallows  Screw  Connectors  ...............................  $22.50 

2.  FOR  MAKING  AND  INHALING  NO.    Wash-Bottle,  Large  Rubber 

Bag,  Small  Bag  with  stop-cock  and  mouth-piece,   i  lb.  Nitrate  of 
Ammonia  ...........................................................    22.50 

3.  COMPOUND  BLOW-PIPE.    2  Rubber  Gas-Bags,  with  tubing,  con- 

nectors, and  jet,  complete  ............................................   40.00 

4.  THE  ARTICLES  in  Nos.  i,  2,  and  3,  complete  .........................   70.00 


The  above  apparatus  will  perform  the  entire  series  of  experiments  with 
perfect  convenience  and  satisfaction.   The  following  can  be  easily  obtained,  viz. : 

Alcohol,  oil  of  vitriol,  muriatic  acid,  aqua-fortis,  sheet  zinc  and  copper,  old 
watch-springs,  starch,  marble,  lime,  charcoal,  scraps  of  tin,  specie-jars,  soda, 
Glauber  s  salt,  salt,  plaster  of  Paris,  gum-arabic,  sugar,  beeswax,  corks,  wire, 
candles,  soap,  plates,  three-cornered  file  for  cutting  glass,  junk  bottles,  and  iron, 
zinc,  and  steel  filings. 

We  are  also  prepared  to  furnish  sets  of  the  chemicals  and  apparatus  necessary 
for  the  performance  of  the  experiments  in  the  chapter  on  Chemical  Analysis. 
Price  $40.  • 

NOTICE. 

Remittance  should  accompany  order  for  apparatus.  If  desired,  however,  it 
will  be  senf'C.  O.  D."  to  customers  enclosing  ten  per  cent,  of  the  amount. 
Money  sent  by  P.  O.  money-order,  or  draft  on  N.  Y.,  is  at  our  risk. 

A.    S.    BARNES    &    CO., 
Ill  &  113  WILLIAM  ST.,  NEW  YORK,  and  113  &  115  STATE  ST.,  CHICAGO, 


j 


This  Index  includes  the  Notes  as  well  as  the  Text. 


PAGE 

CID  ACETIC  198 
u    Arsenious  103 
Benzoic  226 
Boracic  108 

PAGE 

Alkaloids                       212 

PAGB 

Allotropism                   183 

Alum  ....        ....        144 

Benzole  (benzine)  206 
Bessemer's  process..  153 
Binary  compounds..     21 

Carbolic            .  206 

Alumina...                    143 

Carbonic               78 

Chaomic  130 
Citric            ....  211 

Bronze...  174 
Silicate...  143 
Amalgam                       163 

Bitumen  209 

Formic                 202 

Blast-furnace  .  .  150 
Bleaching  103 

Fulminic  84 
Gallic  212 

Amber     226 

Ammonium                   134 

Bleaching-powder...  106 
Blow-pipe  92 

Hydrochloric  .  .   105 
Hydrocyanic.  .  .     84 
Hydrofluoric...  106 
Hydrosulphuric  117 
Lactic  193,  230 
Malic         .        .  211 

Ammonium     Car-  1 
bonate                 \   J35 

Blow-pipe,     Oxy-| 
hydrogen  )     ! 

Ammonium  Chloride  135 
Nitrate..  135 
Ammonia   ...                47 

Bone-black.                   70 

Nitric        -44 

"     Valerianate  204 
Anhydride                     29 

Brass        .               .  .     173 

Oleic         ....      2*8 

Bread  ....                      232 

Oxalic  210 

Arsenious  124 
Nitric  44 
Sulphuric  114 

Brick  154 

Palmitic  218 
Phosphoric  31 

Brimstone  113 
Britannia-  ware  173 

Prussic  84 

Animal  charcoal  70 
Anthracene  208 
Antimony  173 
Antozone        .      ...      40 

Bronze.               174 

Pyrogallic  212 
Pyrofigneous  .  .  205 
Silicic     .        ...  109 

Bunsen's  burner  90 
Burning-fluid  224 

Butter  229 

Stearic                  218 

Aqua-ammonia  48 

Sulphuric  115 
Sulphurous  114 
Sulphydric  117 
Tannic  211 
'     Tartaric  210 
cids  22 

Aqua-regia  105 

Calcimine  137 
Calcium               ....     136 

Arseniuretted  hy-  1 
drogen  f 
Asphaltum         209 

Carbonate...  138 
Chloride  106 
Hypochlorite  106 
-Light  90 
Oxide  ...         136 

1     Vegetable  210 

Atomic  theory,  21 
"       weight  19 
Atmosphere  96 

Ibumen  228 

Phosphate  .  .  140 
Sulphate  139 
Sulphite  140 
Calico-printing  216 
Calomel                         172 

[cohol  196 
Definition  of.  202 
"        Methyl  201 
"        Phenyl  206 
Icohols,  The  201 
idehyde  199,201 
lizann  208 

Atmosphere,    Per-  j 
manence  of  f 

BALSAMS  225 

Camphene  224 
Camphor  224 

Barium               .            140 

"       Chloride  140 
Barvtes...                 .  .  IAO 

Candles  ....                   221 

Ikalies...                .    2* 

Caoutchouc  .  .          .  .  227 

S10 


INDEX. 


PAGE 

Carat 65,174 

Caramel 191 

Carbon 64 

44       Disulphide...  118 

Carbonic  Acid 30,78 

44         Anhydride.    73 

44         Oxide 77,80 

Carburetted     hy  -  j  a    Q 

drogen ...f8''82 

Carmine 217 

Case-hardening 152 

Casein 229 

Cast-iron...   151 

Catalysis  . . . '. 29 

Cells 186 

Cellulin 186 

Chalk 138 

Charcoal 67 

Cheese 229 

Chemical  affinity 17 

Chemistry,  Organic..  179 
of  candle.  86 
44  lamp..  83 
44  fire....  85 
Domestic  232 

Chilled  iron 151 

Chlorine 102 

Chloroform 198 

Chloral,  Hydrate  of..  198 

Choke-damp 77 

Chrome  yellow 130 

Chromium 130 

Cinnabar 170 

Cider 198 

Clay., 143 

Coal 71 

"  -fi*8 


"  -oil 208 

"  -tar 206 

Cobalt 123 

Cochineal 217 

Coin 174 

Coke 72 

Collodion 190 

Compound  Ammo- 
nias   

Compound    Blow- 
pipe   

Compound  Ethers. 
"          p.,,ii,..,- 


203 
90 


204 
Radical..     84 

Combustion 33,85 

Concrete 137 


Confectionery 

Copper 

n      Acetate  .... 

44       Carbonate.. 

44       Oxide  

44       Sulphate.... 

Copperas 155 

Coral 138 

Corrosive  sublimate.   172 

Cotton 189 

Cream 239 

Cream  of  tartar 210 

Creosote  — 205 


PAGE 

Cupellation 165 

Cyanogen 83 

DAGUERREOTYPE 167 

Davy's  Safety  Lamp .     89 

Decay 204 

Dextrine 185 

Dextrose 191 

Diamond  65 

Diastase 194 

Diffusion,  Law  of 97 

Disinfectant 106 

Distillation 196 

Distillation,      De  -  ( 

structive |    2°4 

Drummond  Light  —     91 

Dyads 139 

Dyeing 216 

EFFLORESCENCE 59 

Elements 17 

44        Symbols  of.     19 
Empirical  formula. . .  128 

Essences 223 

Etching 45 

Ether 197 

Ethers,  The 202 

u        Compound..  204 

Ethyl 200 

44      Butyrate 204 

4t      Hydrate 201 

44      Hydride 200 

44      Oxide 202 

FATS 218 

Fermentation 192 

Ferric  Disulphide —   155 

Fenous  Sulphate 155 

Fibrin 230 

Fire-damp 77 

Fire-works 130 

Fish,  Breathing  of...     6r 

Flame 85 

Fluorine 106 

Force,  Correlation  of    35 
Formula,  Empirical. 127-8 
44         Rational...  128  ' 

Fulminates 84 

Fusil  oil 201 

Fusible  metal 173 


GALENA 159 

Galvanized  iron 156 

Gas,  Carbon. 67 

44     Illuminating ...     82 
44     Diffusion  of....     97 

44     Olefiant 82 

Gelatin 230 

German  silver 173 

Glass no 

Glazing  of  pottery-  / 

ware f     44 

Gluten 194 

Glue 230 

Glycerin 219 


PAGE 

Gold 162 

Graphite 67 

Gum 186 

44    Arabic 186 

4    Benzoin 226 

44    Lac 226 

Gun-cotton 189 

Gunpowder 129 

Gutta-percha 228 

Gypsum 139 

HALOGENS 102 

Hartshorn 47 

Heat 18,33 

Hematite 154 

Homologous  bodies.  200 

Humus 204 

Hydrates 30,58 

Hydraulic  cement. . .  137 

H  ydrocarbons 85 

Hydrogen 50 

Hydrogen    sodium  I 

carbonate )    I34 

Hydrogen   sulphide.  117 
Hydrogen,    Heavy  I      „ 

carburetted....  )       2 
Hydrogen,      Light  I     Rr 

carburetted....  f     ' 
Hydrogen       phos- i 

phide j 

Hydrogen      potas- 1       - 

sium  carbonate  } 
Hydrogen  tones 55 

INDIA-RUBBER 227 

Indigo 217 

Ink.  212 

44    Printers' 103 

Iodine 107 

Iridium 169 

Iron 148 

4    Carbonate 154 

14    Disulphide  . 155 

44    Oxide 154 

4    Sulphate 155 

44    Sulphuret 265 

Isomerism 183 

Ivory-black 65 


KEROSENE. 


.  208 


LAMPBLACK 70 

|  Laudanum 213 

Laughing-gas 46 

;  Lead 159 

44  Acetate 161 

44  Black 67 

44  Carbonate 161 

44  Dioxide 161 

44  Red 161 

44  Sugar  of 161 

44  Tree 161 

44  White 161 

Leather 211 

Light 18 


INDEX. 


811 


PAGE 

Lignine                         186 

PAGE 

Nitrogen  41 

PAGE 

Potash  Bichromate  ) 

Lime                          .  136 

Nomenclature  19 

lSli,DH,UIUlU«U.C  j_     J3Q 

44    Carbonate  of.  .  .  138 
44    Chloride  of.  106 
41    Sulphate  of.  ....  139 
41    Phosphate  of.  .  .  140 

Nordhausen     sul  -  I 
phuricacid....  f  "4 

OIL,  Bitter  almonds.  .  206 
Castor    222 

Carbonate  of  127 
Chlorate  of..  130 
Nitrate  of  ...  129 
Picrate  of  .  .  •  206 
Prussiate  of84,257 

phate  of              f   X4° 

Fusil             .  .      201 

Potassium....               126 

Pottery  144 

Practical  Questions.      40 

49,63,94,118,146,176,236 

Olive        222 

Preserves     .  .  .        192  199 

Problems        .                24 

Logwood  217 

'     of  vitriol  115 

Prussic  acid  84 

O  Is                               218 

Putrefaction      .           231 

Lye                ....            128 

Olefiant  gas  82 

Pyroxylin  189 

Olein               ....          218 

Magenta    .  .  .                 207 

Oreide     175 

Quartz        .        109 

Magnesium  141 

Organic  acids  210 

Quicksilver  170 

44          Carbonate  141 

44        bases  212 

Quinine  214 

44           Citrate....  211 
Sulphate..  142 
Malleable  iron  151 
Malt  193 

14        chemistry..  180 
Organic      coloring  j       , 
principles  j 
Organic  radicals..  .84,200 

RADICALS  84,200 
44         Salts  of  203 
Red  precipitate  172 

Manganese      .             155 

Organization       of  \ 

Marble...                 ..   138 

matter  ) 

Resin  ....         .     .        225 

Marl  138 

Osmium.              169 

Rochelle  salt                211 

Marsh  -gas                       81 

Oxygen                           27 

Marsh-gas  series....  200 

O  x  y-  hydrogen  j 

Rosin      225 

Marsh's  test  124 
Matches  .  -  •             "       121 

blow-pipe  )     y 
Ozone       .                      38 

SAGO                              185 

Mathematics       of   ) 
chemistry       .    j       ' 

PAPER  188 

Sal-ammoniac  13.5 
Saleratus                 .      128 

Mauvre                          207 

Paraffine         .               205 

Sal-soda                         137 

Mercury                        170 

Parchment                    189 

44        Chloride    .    171 

Paregoric        .     ...     213 

44     Epsom.  .  .  .           142 

Metals          ...               126 

Pearlash                .  .  .     128 

"      Alkalies  126 

Peat  72 

44     Rochelle  ......  211 

Metals,       Alkaline  I       ,. 
earths                  f   X36 

Pectin  186 
Pencils        67 

Salt  of  tartar  (sal-  } 
sodai)                   i     33 

Metals,  Earths  143 

Percussion  caps  84 

Salts  22 

44        Noble  162 

Permanence  of  at-  I 

44    of  the  radicals      203 

44        Useful  148 

mosphere            J    I( 

Methyl  200 

Peruvian  bark.      ..     214 

Salted  meat  -     .           232 

44      Alcohol   .         201 

Petrifactions  ...           no 

Saltpetre                        129 

Methylated  spirit         201 

Milk  239 

Pewter                  ....  173 

Sand  ....                        109 

Mirrors.          .  .  .            171 

Phosphate      Acid  ) 

Secretion                       187 

Mixed  gases                    52 

calcium               f  234 

Shellac                          226 

Monads        139 

Shot                                174 

Mordant  145 
Morphine  214 

Phosphuretted  hy-  j 
drogen            .  .  f 

Silicon  109 
Silica     no 

Mortar        .        ....     137" 

Muck                       ...     72 

Picrates  The                206 

Silver                            164 

Musical  tones  55 

Pitch  .  .  .                    224-5 

44      Chloride             167 

Plants  in  the  room..     98 

44     Nitrate  167 

NAPHTHA  208 

Plants,  Office  of.  100,181 

Smelting  ....                149 

Napthaline  208 

Plaster  of  Paris           139 

Soap                               218 

Nascent  state  49 
Nickel        173 

Plastering  137 

Soda,  Bicarbonate  of.  134 

Nicotine                        214 

Nitre  .    .                      129 

Nitric  oxide          .          46 

44     '  Bicarbon-  V 

Nitrous  oxide  46 

ate  of...  f  I28 

44      Carbonate...  133 

INDEX. 


r 
Sodium,  Chloride  of. 
11       Sulphate  .  .  . 

AGE 
131 
133 

100 

173 

18 
70 

I4I 
156 

54 
93 
138 
139 
184 
218 

152 
140 
214 
107 
190 
190 

X 

j 

Sulphur 

AGE 

"3 
117 
19 

211 
I85 
205 
211 

133 
215 

J57 
224 
172 
217 

159 
170 

79 
198 

159 

1 
Vitriol  Green 

AGE 
155 
II4 

157 

56 
137 
221 
l6i 

161 
139 
195 
205 
20  1 
205 
205 
186 

193 

156 
157 
157 

Sulphuretted    hy  -  I 
drogen  j 
Symbols        

44       Oil  of.  .  . 
"       White  

WATER... 

Solder  

Solution  

Soot  

Water-lime 

Spectrum  analysis..  . 
Spelter 

Tapioca       

Wax  

Tar 

Spongy  platinum  
Spontaneous   com-  1 
bustion                f 

White-lead 

Tartar,  Salts  of  (sal-  | 
soda)  ) 

Whiting... 
Wines 

Stalactites 

Tea 

Wood,  Distillation  of. 

Stalagmites 

Tin 

Star-en 

Turpentine        .... 

14      -vinegar  
Wood-tar 

Stearin 

Type-metal       .  . 

Steel        

Tyrian  purple  

Woody  fibre  

Strontium 

VERDIGRIS 

YEAST. 

Sublimation  

Vermilion  

ZINC. 

Ventilation  
Vinegar 

u    Sulphate 

"      Grape  

Vitriol,  Blue  

14    White  

"      of  lead... 

A  .  .__ 

^^ 


—  I  — 


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